Capitec/Libery unprofessional service

I lost my job in 2019 and paid my installments up until about 6 months ago. I had a refund from Liberty which they decided to transfer to Capitec instead of my latest bank account which I updated with them. I have not been able to make payment arrangements as I currently do not have a source of income. I have explained the situation on numerous occasions with their accounts contact. Is it legal that they should keep an overdue account on standby and forcefully take an installment even if it's clear that was not a salary and also not a regular income?