Migration headache

Very disappointed with poor service received from Discovery Bank. I have been struggling to migrate from Discovery card to Discovery Bank since October 2019. They debited Discovery Bank with the full credit limit instead of just transferring the outstanding balance. That means I dont have any credit available and I use the card for all purchases in order to earn discovery miles. Been struggling since Friday 15 Nov to sort out this mess. Call centre agents unable to help and only make empty promises. I am seriously considering closing this account.