Poor service by Nedbank

I have a loan with nedbank since 2019 iv been paying well never missed a payment untill they decided not to debit this year July and August without any communication, been sending emails and calls but no answer, its affected my credit score, now when reaching out to them about the issue on what happened and whar arrangements can be made to clear the arrears, they not responding to emails, and it's a really inconvenient, Please help me out by getting their attention on the matter. Been very loyal to them since 2009.