4 months since claim sent in, device still not collected

It has been 4 Months since I put in a claim for a tablet screen. Since today no one has collected. A poor excuse that they cant find my address. But other courier companies deliver to my house daily. Its a normal house address. How the hell can Mtn partner with this company. I have 3 contracts with MtN and I will not be renewing them. Mtn is a big company that can surely ensure their "partners" take care of thei clients. I am fed up.