MFC can't explain extra money that's been added to my account

I have been requesting statements, answers, feedback..... but no such luck.

My account with them should have been paid off end of March (this was my last installment) but due to circumstances I couldn't pay end of March.

Eventually money was paid end of May 2020.

Now they reckon I owe them another month's installment... I ask them to explain but I don't think they know either as they keep referring me to the statement or they just don't answer me.

I know that payment was late but how charge me a full month's installment.... now I get this sms:

Reminder: The arranged payment of R3,285.02 by means of debit order for vehicle account 13786***x01, is due on/before 27 Jun 2020. MFC

NOTHING HAS BEEN ARRANGED!!!!!

Then I can only speak to Phumzile Mhlungu.... I might as well be speaking to my 3year old.

You complain on the website, they forward the complaint to Phumzile and send you an sms saying complaint resolved! Really???

Phone them, no one BUT Phumzile can assist, she doesn't answer, if they transfer me no answer.