Pathetic service

I Am on maternity leave and receiving payment from UIF as from July 2017,I have a Woolworths account and my monthly installment is r600 and I've been paying half the amount ,Woolworths then called and I informed them that am on maternity leave and cannot afford my installment and then they insutructed me to continue paying minimum of r300 to my surprise my account has been handed to Mbd for collections saying I must pay r1000 at the store to continue using my card or mid will be debiting my account. I don't understand why and what is the reason my account is handed over.