Lost proof of payment

I am utterly disappointed in Mtn, I Paid my Mtn account on the 15th of April via cash deposit at ABSA ATM.

Being a complete fool I lost my deposit slip, yes completely idiotic on my part but the thing is, I was able to confirm that the payment was made successfully, ABSA Could confirm that the transaction went through and payment was made to Mtn. The amount, date and reference is all on their system but for some unknown reason to the universe they cannot give me a proof of payment... Something about it being a cash deposit at an ATM.

So I gave all the details of the transaction to MTN. time date deposited amount references but no... Apparently Mtn receives millions of payments in one day and it is impossible for them to find my payment and allocate it to my account... They won't even take the time to look.. I will definitely be canceling my contract.. My only advice.. Please don't ever lose your proof of payment when dealing with MTN.. Without it Mtn will pocket your money and smile all the way to the bank..