AVON ruining my credit record

After AVON billed me for a box I had returned to them, I contacted them and I spoke to Thoko Skosana who informed that there was nothing I could do to fix it. I decided to just pay it off as it is ruining my record. I sent them a proof of payment and have not heard from them upon receipt. I expect receipt of payment and steps taken with credit bureau so the debt they had put in my name is paid and not escalating.