Credit damage

I payed my account in full to an extent that Exact owed me R1, but I kept on receiving call for me to join the magazine what what that I did not know of, and I told them no I don't want it, even though they kept on saying I must try it out for one month, still I said no. Now my credit record is at stake because they say I am in areas by R57 that I don't know of. If they say I joined, then I must be provided with the recording that I said yes.