Poor Service and Negligence

have always bought phones at Pep stores without issues,but this time around, I was at PEP store at Kwagga mall Pretoria west to purchase 2 phones and when I got home,only to find out the phones were locked with a particular network,and i took the phone back as it was not working with my chosen network,only to be told by one of the attendant that I need to port my line to another network ! and I asked him why I should do that ? you cant make me port ma line simply because I bought a phone locked to network,the least you can do is change the phone to my preferred network,unfortunately he was answering rudely I demanded for the manager but to no avail,nothing could be done ,now am sitting with 2 phones that I cannot use ! Thanks to them