Complaint of bad service

I have an account with Avon *** I made a ayment to this act and also emailed proof of payment to them on 28/02/22 and received feedback confirming payment received. However 7 days later I received a text to advise I am been handed over if payment is not done immediately and ignore if done. Which was my mistake to ignore as now I get calls from ITC doing collection of funds Avon has received. I have tried advising this has been done and that I could send proof of payment and this department wants nothing to do with this unless payment is done again to their account or else further blacklisting.

I am really appalled at the service recieved and for me to be sent from pillar to post with no resolution, I am even afraid to continue as an agent if my customers pay Avon and I also need to pay Avon means that I am not making that extra I come.

Furthermore I am worried about my credit file as this will affect my future looking for a job or even application of finance that may be needed.