Mtn ****ing people paying facke accounts.

What to know how do mtn opperate. January they offered me a account that i toke, but with arranchment if i change my my mind i just need to return the device and sim that i dit. Nearly the year has passed and now some attorneys of mtn are asking when am i goning to selte R2650,04 of witch they cant tel me for what thise is for. I want to know do mtn randomly pick people to be handed over to attorneys and expect them to pay account that they do not have?

To top all of this i whent to mtn and they do not find me on there database, seriosly????