bad customer service at MTN

i’ve had the mtn free to use router for a couple of months now & a few weeks back it overheated when i away for about 2 weeks & it is disfigured & also it doesn’t work properly anymore. so i tried to take it to my nearest mtn store they told me they’re unable to help me because i got helped online when i app**** for the router, i when got home & tried to call i’m being told i should be able to get help from the store which makes sense to me. today i decided to go again & try to return it, same thing is happening the people who work in there don’t want to help so it’s a back & forth type of situation. i’m actually ****ed to say the least, i don’t want their router anymore & it is not my problem that it overheated & that it doesn’t work properly anymore.