CELL C FAILING TO GIVE ME PAID UP LETTERS FOR THE CANCELLED CELLPHONE CONTRACTS

I am hoping that I am writing this complaint for the last time. I've been calling Cell C for a while now requesting for paid up letters for the contracts that I have cancelled and paid up.

I need these letters as proof that I no longer have cellphone contracts with cell c. Please send me those letters because if this fails I will be contacting the ombudsman.