Debit Order gone wrong

Am so annoyed with Fnb home loan at the moment , I am even thinking to move it to Capitec homeloan.I got an SMS on the 30th of December that my account is in arrears and to come to my suprise there was money in my account, I called I spoke to the consultant and he advised me to do manual payment and send him pop, on the 5th of Jan 2022 I got an SMS that my account is in arrears I called I spoke to some guy he put me on hold for more than 15 minutes and no response, on the 06th I get an SMS of letter of demand , I called an spoke to Cornelius he said he will log a call to check , later I got a call from a lady who didn’t even want to understand or listen to my dispute telling I owe R2600 arrears I need this to be fixed or pay back my R3395 I paid on the 31st Dec then I will pay double on the 26 January.