Bad client service

I have an active account with zone fitness that is up-to-date and daily I am receiving a call and messages from Nimble group for my zone fitness account that is handed over. I have spoken to different personel at zone fitness and all they will tell me is that my account is active.

Nimble is telling me zone fitness handed me over to them and yesterday I was at zone fitness and they confirmed again that all is good. Today I receive a call again about assistance in repayment for my handed over account.

This is affecting my credit score and no one is willing to sort this out. I am really frustrated with this level of incompetence. Can someone help sort this thing before I escalate it to the legal route.