Very bad client service and bad quality control

Im finished with paying all of my accounts, they then said before taking me off from debt review, that they needed a payed up letter with the correct account number, not the one i gave them on my payed up letter. But every time i paid up an account i get the settlement letter, the proof of payment letter and the payed up letter, and email it to debtgrip (which is them who is actually suppose to get those letters). How on earth do they have another account number that is not mine? And what happened to the letter i send them long ago? When i payed that account finished, they were supposed to ask the company for a letter, why they never did it. So now you can forget to call them, i made 38 calls in 2 days, trying to get hold of them, unsuccessfully. They said they have a whatsapp number, well you can send it but it wont get read by them. Today is 24 January, going to their whatsapp status, it says last seen 12 January, so what is the whatsapp number for. I am Finnish with debt review, and just would like to get off now since i paid all my accounts in full, dont come with other stories that my account numbers are wrong, please.