Wanting a letter from my bank for proof of payment

good day about two month ago i bought a top online however never got my goods and started following up on the item, spoke to a guy by the name of Asanda wich advise me to get a letter from my bank to prove that the payment was made my bank dont give any such letters and Asanda at Mr Price is insitting in having a letter i have no time to stand in the bank and ask for a letter that the bank can not even give to me however i did mail my bankstatement with the payment of MR Price on my statement and Asanda would not accept this, this is not the first time i have shopped with Mr Price and never had aproblem why cant they go and check on their statement for my payment cause everything works with a reference number my no ********** 16217 and payment was **** on the 26/11/2017 proof of my payment was mailed to ********** today again i just need them to sort out this query cause it is over two months now. contact number **********