Disgusting customer service from Rain

I went to MTN to buy a new 4G LTE MIFI Router for my 4G Rain sim card. Rain states on their webpage that their sim card will work in ANY 4G enabled device. Well it does not! Mtn is also to blame here as they sold me the router after I specifically told the lady at MTN Mall of the South that I would be using a Rain sim card in the device only to find out that the device is MTN Sim Locked! Now here's the kicker....I phoned Rain to ask for help. Firstly, they cant sell me a 4G router, and secondly, then after I said that I may as well then cancel with Rain, she pretty well told me to do just that! No effort to retain a client. Absolutely no concern for the companies financial well being at all ! Rain customer service SUCKS !