Debit Order not running on the agreed date...

I am now running out of ideas on what to do with MTNSA, on the 15/04/2015 MTN did not debit my cheque account as agreed they sent through the debit order (D/O) on the 24/04/2015 there was no money in my cheque account, i went to the branch in MENLYN on 27/04/2015 and paid in cash and requested the D/O date to be changed to be on the 1st of every month again they sent through the D/O on the 15/05/2015 there was no money i went to the branch in CARLTON CENTRE in JHB they were refering me to the Morningside i don't have time to go to Morningside hence i did the D/O. Now again they sent through another D/O on the 18/06/2015 i have sent emails to [Email Removed] made calls and went to the branches to request this change of date to be the 1st they don't change since this is the day of my salary. All this other years D/O was running on the requested date suddenly things changed. My bank is busy with me on unpaid D/O's and my credit profile is being damaged by MTN intentionally because i have addressed this matter with them. They can't just go into my personal cheque account and try deduct money on their own date. I WANT REFUND ON ALL LOSES SUFFERED AND DAMAGE CAUSED BY THIS