The connect finance department for Hifi Corporation is absolutely disappointing and a waste of my time as a loyal customer

The connect finance department for Hifi Corporation is absolutely disappointing and a waste of my time as a loyal customer. They debited me an amount of R789 which is my usual monthly installment however for December was the last debit which was only supposed to be a balance of R316.40. I have tried calling them on numerous occasions and I get put on hold, I have emailed them and have not received a response to date. I went to the extent of going in store, the sales assistant tried calling them to which she was also put on hold. I was then told there is nothing they can do to assist me and I should just continue trying to call... This is really frustrating because I am now left with no help from the store and to continously call a department that does not answer! Needless to say that I will not purchase any products in future from Hifi Corp, be it credit or cash because of very poor customer service.