Mtn "sigh"

good day I have been an Mtn subscriber for a number of years on multiple contracts & I have been mildly disappointed in the past, not enough for me to want to end my relationship with them. HOWEVER, a few months ago I extended my business with Mtn by signing on a 1TB data LTE contract. while I still use the service, I must say I am very very disappointed with download & upload speeds. I have done the necessary checks of hardware & all other matters before complaining to my service provider, who change the simcard & did all that he had to do, with no success, eventually he escalated the query to the person responsible for such queries, we got speaking & asked me to do a number of tests which I did. AND I AM STILL WAITING. I pay my bill every month & have never had a late payment, but I certainly have a compromised service. their speeds are a joke, I might as well buy a copper based service for half the price, I will achieve the same thing. To Mtn, I do not want to end my business with you, I am a believer of loyalty, but a person can only accept so much. Please can you assist me, i am not asking for a lot, i am asking for what i think i am owed or what i am paying for. PLEASE....