Robbing my money

Truworth cost me a bad credit report. I bought merchandise on 6 and 9 months. My premium is R180 a month that i pay myself and pay EVERY month. Now all of a sudden the took a debit for the Full acount balance. That ***** in my eyes as i didn't approve that debit order. Is truworths going to give. If i was a non or slow payer maybe i can understand. But WHY take the whole amount? then there is no use to have credit and i can buy somewhere else for cheaper.