Mtn Poor Service

Poor Service from Mtn/Axxess bought a Nokia 5g Gateway Fastmile 3.2 router which is on the list of their Mtn approved routers for 5g but they mtn keep on locking their simcard I'm paying around R1000 for their mtn 5g package but they are failing to solve the problem they keep lying and never call to give any updates or find a solution