AVON REFUSE TO PAY MONEY BACK THAT DOESNT BELONG TO THEM

I paid an amount of R700 erroneously into Avon's account. I gave them proof that the payment was made by me and I attach a letter from the representative who's account it was that the money can be paid back to me. 7 weeks later after more than 1 emailed I send to Avon, Avon made no refund and are completely ignoring me. We are in lockdown since March and everybody is financially struggling but Avon refuse to give money back that doesn't belong to them. Also found out that other people also requested refunds from Avon and after 11 months Avon still made no refund to them. Does Avon think they are above the law? If you know the money in you account is not yours but you refuse to pay it out, you are in all aspects busy *****ing from people. I want my money paid back to me!!! I will never buy anything from Avon again or do any business with them.