Spectrum customer experience

I went in nearly two weeks ago to hand in my modem after having closed my account. I wasn't given any documentation of having returned it and after walking out I thought better of it, so went back to request some proof, just to be thorough. I'm going to do Asst. Store Manager Alex the courtesy of suspending my disbelief and assume he's not aware of the condescending tone he takes with people. When I asked what would happen if I don't receive email confirmation he says "trust me...", which isn't reassuring to strangers, and surely won't be defensible if I end up with a massive charge for equipment I now cannot prove was returned. Just be decent to people. And to the branch: consider amending the returns process to be more official.

This weekend, I received a notice in the mail that Spectrum has not received my equipment and I’m at risk of having to pay the replacement fee. This is exactly what which I had informed the storefront employee I was afraid. Please advise on how to resolve this.