Returned MTN LTE+ Router and Simcard within 24 hours...not able to stay connected.

I purchased a MTN Fixed-LTE 20 Mbps contract on the afternoon of 2nd November 2021, I have spent the whole night and half of the next day trying different routers and settings to get the simcard to stay connected, it connects at MTN LTE+ but there is only upload data and 0kbps download . . then it disconnects and reconnects and stays connected for about 10 minutes, then it disconnects, and then i have to switch the ZTE Router off and on again multiple times before it reconnects, i have the same issue with the Huawei Router i have borrowed and the MTN Simcard . . .i spent the whole day with MTN support on the 3rd of November, we couldnt get the problem solved,it keeps on disconnecting and struggle to re-connect...it stays off for hours at a time , even if i restart the router/power it off. I took the router and simcard back on the 4th of November 2021 . . i am struggling to get someone at Retentions to phone me back after numerous calls to them . . i spent two weeks with MTN over the phone, i have been back to the shop 8x times. i left the router and simcard at the MTN shop on the 15th Nov. I am still struggling to get MTN to cancel that horrible service and contract.