Blacklisting me

I have made payments into my deceased mother's account from November 2021 till April 2022 as Telkom failed to supply me with the new account details and when I instructed them to do an audit on her account and transfer the additional money into my account due to their failure they refused now they have taken me to debt collectors to blacklist me. However, I have made payment and Telkom is too lazy to do the audit. If they did they would never have done this. If I am blacklisted because of their incompetence firstly not supplying me with the new account details to allow me to pay it into the correct account, secondly not wanting to do the audit on the old account and move it to the new account. Thirdly making me out to be the culprit by sending my account to a debt collector although the money is already with them.