Questions of Cash: We get a £6,000 winning result after Premium Bonds puzzle

Q. I registered for online management of my Premium Bonds some years ago, but I have since lost the registration details. I tried to check on them using the MyLostAccounts online facility, which NS&I is involved in.

I entered all my personal details, but the response came back that there was no record of investments in my name. This is clearly wrong, as I also have certificates of investment in my name at my current address, which were taken out by my father and left to me in his will and reassigned in my name.

I made these points in a letter to NS&I back in March, but I have not any reply, even an acknowledgement of this latest letter. Can you find out what the situation is please? I would like to know the full value of my Premium Bonds and whether they have been lucky in any draws. PN, Northern Ireland

A. Your request specified Premium Bonds and children's bonds, not the savings bonds that were the subject of your certificates of investment. Although you listed several former addresses, these did not include the address where the Premium Bonds and children's bonds were last registered.

It seems the tracing service looks at the last address registered, without cross-checking against previous addresses. With the additional address you have provided, NS&I has established that you hold income bonds to the value of £24,000 and five-year index-linked savings certificates to the value of £6,057.70.

Each of your two children has children's savings bonds to the value of £2,614.32. You have Premium Bonds to a total of £65, but none of these has been successful. You tell us that although you are disappointed not to have won with your Premium Bonds, you are very pleased to learn that you have more than £6,000 in savings certificates of which you were unaware.

Q. Scottish Gas is trying to claim payment for energy used in a property I left 13 months ago. It has billed me for £181.02 and instructed debt collectors to contact me. Before I left the house I submitted an online meter reading and paid a final bill of £91.86 in April last year. It seems Scottish Gas's mobile app misread the meter.

When I spoke to Scottish Gas, I was told there had been an incorrect meter reading, but this must have been investigated by Scottish Gas at the time. The new bill, dated March this year, uses an incorrect estimated reading. The rules on back billing are clear that Scottish Gas is not allowed to do this "where a customer has provided correct readings, but a supplier has rejected them without investigation as invalid".

The back billing rules also state an energy company is not allowed to charge more than a year after the period of consumption. At best, Scottish Gas is entitled to charge for the period 28 March to 11 April. This is the period from a year before this year's bill and when I left the property. I have told BG on several occasions that they are not applying the code properly, but it insists that I must pay the bill. TD, Scotland.

A. Scottish Gas now accepts your interpretation of the back billing rules. It seems that these were misunderstood by a member of staff, who has now been sent for retraining. Spokeswoman Carol Aitken explains: "We are sorry for the error we made when dealing with [the reader's] back billing request. Our agent made a mistake.

The rules on back billing are quite clear and they state that if the supplier is at fault, it will not seek additional payment for unbilled energy used more than 12 months prior to the error being detected and a corrected bill being issued. We did not apply this principle in [the reader's] case. We have apologised to [the reader] and written off his outstanding debt of £215 as a gesture of goodwill."

Q. I ordered a digital tablet from Coopelectricalshop.co.uk for my wife's birthday, for delivery on 3 May. It was to be delivered at 13.00 on that date by DPD. I waited at the address and checked the DPD website for any delay, but it showed "no delay reported". As the delivery time passed, I received a message on my mobile saying the driver had been delayed and delivery would instead be at 18.00 but I could not stay until then, so I arranged for a new delivery time on 4 May. I stayed in and again no delivery.

I checked my emails and found that DPD had claimed the driver could not obtain access to the address. It turns out the driver could not get through the main entrance door and had not seen the external buzzer for our apartment. I then agreed for delivery to be to my workplace. But instead the driver delivered it to another company nearby. I could not give my wife her present on her birthday. I have been let down by Co-op Electrical's delivery company. ZN, London.

A. DPD and Co-op Electrical, part of the Co-operative Group, agree you did not receive an acceptable service. DPD initially agreed to pay compensation of £50, which has been increased to £100. The Co-operative Group will also pay £20 compensation to apologise for the way it dealt with your complaint. You have accepted these offers.

A spokesman for Co-operative Electrical said: "DPD do have industry-leading standards and we have been assured that lessons have been learned and that our customers can expect to continue to receive a high level of service." Your compensation is equivalent to the cost of the digital tablet, as well as now receiving the ordered item.

Questions of Cash cannot give individual advice. But if you have a financial dilemma, we'll do our best to help. Please email us at: questionsofcash@independent.co.uk