Trying to cancell contract but very bad MTN customer service!

My wife had a MTN cellphone contract and she passed away April 2022. I went to the MTN office in Herm**** but was told that i must cancell the contract online. I phoned 135 and had to hold on for nearly an hour, and could not get through. On 14/6/22 I E mailed MTN customer care, explaining the situation and asked that the contract be cancelled. I received an E maill with reference number. From then on I was comunicating, sending info that I was aked for, like statement, ID number, I even supp**** them with a death certificate, proving my wifes death. By 20/9/22 I informed MTN by E mail that nothing has happened and am still receving statements, which was paid by debit order. Then I was informed that my query is in a waiting que with a reference number. On 14/10/22 I got a e mail from Joe Jacobs with a new E mail adress asking for details. On 31/10/22 I asked that the matter could be settled, as I was then trying to do it for 5 months. On 31/10/22 I got a response with a reference number.. On 11/11/22 I supp**** the acount details for the second time. On 18/11/22 a thank you letter and was advised to contact 135, which I did in the pass iwthout result. I am still receiving statements and realy do not know what to do to resove this matter and cancell this contract! This is realy very bad service!