Horrible experience with accounts department

Shocking service from the accounts department. Debited me for a product I never went ahead with. Been phoning account department for 2 weeks now only to hear every time the credit note still needs to be processed and they will escalate it. Every time I phone in they start all over again with the credit note. Then when I refused to pay my next monthly normal installment I received harassing calls all day about my tracking unit being cancelled etc. can someone there just do their job?