disgusted and vey disappointed

I have an Avon account however I paid up my account october 2015 since then i kept the account active but haven't used it. for the past month i am harassed by calls from ITC business administrators telling me i have an outstanding balance with Avon that needs to be paid , i sent them my **** of payments from FNB online banking since i made payments via online banking cause avon was a beneficiary they tell me the proof of payment is invalid. I am getting tired of the calls I am getting ,as it is Avon listed me as default which is affecting my credit report as I speak so get all your facts straights before you start listing people as dafaults and inform people when there's outstanding balances on their accounts cause i never got any correspondence from you guys stating that i have an amount outstanding on my account.