Harassment due to ABSA's own problems

I obtained a personal loan for ABSA November 2015. I signed and had confirmation via a letter that the payment would be done trough an internal ABSA debit order from my cheque account. For December 2015 payment the debit order went trough. But on 25 January no debit order went trough with the account stating \intreater rate\" on that day. I then received a letter in the post stating that the debit orders wil resume on 25 February with the first paymnet being double. YET, despite this I am harassed at least twice a day by ABSA collections phoning and sms'ing form unknown numbers and being very impolite and not admitting absa's own errors. They even threaten my credit records. Now I will gladly pay any arrears if ABSA system can just decide and inform me once and for all if they will set up an internal debit order or not. Bad service ABSA!"