incorrect billing

I had an existing loan at OMF which they squashed and gave a new loan amount for repayment of r1699.00. My salary date is the 27th of each month. Yesterday 23 September 2015 i received an sms saying my debit order were denied. Immediately i called OMF as i never authorised them to deduct on 23/09. The consultant told me to ignore the sms as they have triggers n their debit orders. Yesterday 23/09 i made a purchase at pick n pay and i had a balance of r71 eemaining agter the purchase. Today 24/09 i am in urgent need of aitime and i cant get it cause my account is now in a -1600 and somethng rand and i am furious about this. My contract said first deduction on 25/09. Yet they tried on 23/09<br> This is unacceptable. I have a personal emergency and need airtime and cant even get it as my account now say i have insufficient fund when i still had r71.