No through put on data

I have been logging calls and phoning since November about data problems on my phone and have gotten absolutely no help from MTN. It sometimes takes up to 15 min for a message to go through or be received via data network. On your coverage map it states we have LTE coverage but I have seen the 4G logo once in all this time. No one at any of your customer services centers seem to know how to resolve this problem.<br> <br> My next step will be to with hold all payments until this problem is solved by whoever needs to do it.