My router password keeps getting reset to the default password after I change it.

My router password keeps getting reset to the default password after I change it. This is extremely frustrating, and customer care hasn’t responded to me—they just ignore my messages. It’s making me think that someone at MTN might actually be resetting it on purpose. After the password resets, an IP address with the name "*",this is thier ip address.(
192.168.0.117) connects to my network, and MTN sends me a message telling me my data is finished. This happened with 100GB of data. Even if I were overusing it, finishing 100GB in 24 hours is unheard of.

The customer care representative is just ignoring me. It feels like I’ve paid for a problem instead of a solution. This is a 5G router, yet even my Airtel 4G MiFi was more secure—and it was cheaper.