Debited early without permission

I have a personal loan with Finchoice and agreed with the debit order on the 23rd of every month, which is my pay date. On the month of March their debit order went through the Friday of the 20th of March 2015 and it was reversed by the Bank since there was no enough funds on my account and Finchoice managed to get the monthly instalment for March on agreed date, but the problem now Finchoice blocked KwikAdvance and KwikDraw because they said I'm in arrears according to their system. I've call them and they promised to resolve the matter since it was the error on their side and after that I received the sms stating that the matter is resolved but I still can't access the kwik Advance. I called on the 1st of May and I spoken with Ako Ntingi who told me that she cant help me i'm must just waiting for a sms from Finchoice and I explain to her that I received the sms stating that the matter is resolved and I requested to speak with her manager since she was not helpful and the manager promised to investigate and get back to me before the end of the business, since then I have not received any call from Finchoice. Please let me know if you can't help me so that I can approach Iemas.