Rejected Debi check becomes a double debit in the month of December

Recently I received a message stating that there will be a change in my reference number for my debit order. I then received a debi check mandate for a higher amount which I rejected. Sent an email etc correcting the amount and no communication there after. This month I get double debited with the higher amount that i rejected even though I rejected the debi check. Now I phone to request a refund and I'm not getting the "pop" up message. Now I'm told to go into a branch to request the refund ?!?!?!?!?!? Where do I find the time this time of the year or any month for that matter to go into a branch for a refund in the 21st century???? This is totally unexceptable. And all of this in December. 5 days before Christmas over R3000 put of my account which I need to make time to go to a branch if I want my kids to have a Christmas.