Poor service

Good morning, i opened an account at OK furniture in Aliwal North. I took a cellphone and i had to pay R480 for 6 months and the account was a debit order, for two months the shop did not withdraw money at my account so i thought maybe the is a problem with their system or something so i decided to go pay cash. This month was my last month to pay the account and i was not aware that they still didn't withdraw their money from my bank account, till i received the call from Rainbow finance asking me to pay before the 27th this month. I dont have money now and its not my problem that OK didnt withdraw money on my account as i am earning my salary at the end of the month i suggest they wait till month end then i'll go pay their money at the last day of this month.. Thank you