Mobicred Nightmare

I have an account with Mobicred and everything was fine until at the end of January .They did not debit my account as per usual and I got a phone call and SMS informing me that I had to make a payment as the system was unable to debit the account if the payment date was on a Sunday.I made the payment as requested ,and three days later I received another SMS stating that payment was not received. I forwarded the proof of payment and a day later my account was debited for the same amount I spoke to someone on the phone who said they can see both payments , meaning I have made two payments in one month. I am still receiving SMS reminders to make payment ,Mobicred I am sick of it fix your system.