Service Interruption even though equipment returned

I moved in July, and switched service to my new apartment. They gave me updated equipment, and told me to send back the old equipment, which I did.

Months later I am notified that they did not receive the equipment, and my service is interrupted. I speak with a rep online who assured me it is an error and they will fix it

A manager now says without the tracking they cannot fix the issue. I don’t have it anymore since it has been so long, and cannot pay $250 for something I don’t even have, and need the internet to work from home and for my daughter to do home school.