Those on prepayment meters are missing out on more than £22million worth of energy bill support vouchers.
All households across the UK received a £400 discount on their energy bills from October 2022 until March 2023.
This was part of the Energy Bill Support scheme and consisted of monthly discounts worth £66 and £67 which were given directly through energy suppliers.
Those on prepayment meters needed to claim their support through a voucher scheme.
In total, around 10million vouchers were issued between October and February.
However, figures revealed through a Freedom of Information (FOI) request by The Times show that 341,000 vouchers are yet to be cashed in.
This equates to around £22 million in support yet to be claimed.
How to claim the energy support voucher
Many of the energy support vouchers were sent by suppliers to those eligible by email, text or post.
They then needed to be taken to a local PayPoint store or a Post Office to be credited onto prepayment meters.
The vouchers must be redeemed within 90 days of their issue date - so if you have not redeemed your February voucher you have until May to do so.
If your voucher has expired, then you will need to contact your energy provider to get a new one issued.
You have until June 30 to request new vouchers for those that have expired.
If you have not received your energy voucher, then you should contact your supplier directly over the phone, by email or in a letter.
In most cases, the supplier will need to ask you questions or update your details to ensure you receive the replacement voucher as soon as possible.
Under the rules, energy suppliers must make at least three attempts to contact customers if a voucher is not redeemed.
So if your contact details are wrong the supplier may have tried to contact you before.
According to the rules, you can use two backdated vouchers in the same month.
So you should double-check and make sure that you have received all of the vouchers you are entitled to.
A Government spokesperson said: “It is vital that every prepayment meter household can access our support to keep their energy bills down this winter - and 78% of these vouchers have now been used by customers.
“Suppliers must make at least three attempts to reach the customer if a voucher is not redeemed and we urge them to continue their ongoing efforts to reach households yet to cash in on savings of up to £400 on energy costs.
“We encourage people to redeem their vouchers as soon as possible. Households will have until 30 June to claim this support and customers should contact their supplier if their voucher is lost, damaged or has expired.”
