Mweb cant upgrade my line although i have been with them for more than a year.

I have been with mweb now for more than a year. The sales guy came to our estate, i took the offer and they came to do the installation at our house. Now more than a year later I want to upgrade my line to a higher package. After 3 weeks i followed up because the line is installed and working but no upgrade has been done. Now the guy apologizes and promise me that he will sort it out. Apparently Mweb invoices me for more that a year and then tells me that the line don't belong to them so they can't upgrade me. so now the second time the issue is escalated. Then my last call was a bit more than 2 days ago, i was told the same thing but i will get a call back between 24-48 hours. still nothing and after more than a month my line is still at the same speed. Mweb... do you even want my business?