Poor management skills and no assistance

I bought a tv wall mount for my tv. It is written for a 37inch tv but when i get home it did fit my tv. I had lost the slip before i even noticed that the wall mount could not fit my tv so i took it back to the shop to have a bigger stand and explained to them that the wall mount had 37inch written on it but doesn't fit my tv but i had lost the slip. The 1st person i spoke to was Manas he was very rude told me i should go back home to fetch my tv so he can see what im talking about because there is no such. i explained to him that i can not drive to soweto to fetch a tv and come back just for him to see that the mount doesn't fit he than said that if i cant do that then he cant assist me its either i bring the tv (which by the way is not their item) or bring a slip. i told him i have the wall mount and it can be tested on any 37inch tv at the shop just to prove my theory, he said they dont have, i ask for his manager above him he said his the only manager and if he cant assist noone will. I insisted on speaking to someone above him than they sent a lady who just insisted that noone can assist and that i must just go i kept on insisting that i speak to the manager abdullah