Chuhar Singh received a £192 demand from British Gas - along with condolences for his untimely death.
Addressed to "the executor of Singh", the letter said the provider was sorry for making contact "at this difficult time" but encouraged existing family members to pay the 52-year-old's outstanding bill.
It said: "We are sorry to learn of the death of the account holder for the British Gas Home-Care agreement.
"We apologise for having to contact you at this difficult time, however we need to establish whether another person in the household plans to continue with the agreement.
"If this is the case, could you please arrange for the enclosed direct debit form to be completed and returned. Alternatively you can arrange to pay the outstanding balance of £192." Mr Singh, who lives with his wife and daughter in Landgate Road, immediately contacted the company.
He said: "I have been with British Gas for donkey's years since I came from India. They said they would send a letter of apology, but I said that wasn't good enough.
"My family were worried to know why there was a letter saying I was dead. Where they got their details from, I do not know."
After informing British Gas he was still alive, it sent "the executor of Singh" two more letters.
One thanked "the executor" for choosing to pay by direct debit, the second thanked him for making contact and provided details of how to obtain a gas appliance check.
Yesterday British Gas admitted the mistake and said it was "embarrassed" by the mix-up.