Useless Vox accounts and their collection agency VeriCred!

Vox Telecom has sent their credit collections agency, VeriCred to collect money for a router I returned to them years ago. I have furnished them with this proof multiple times. To make matters worse when I phone VeriCred to resolve this issue, their switchboard tells me that they're going to transfer me to someone who can help, they put me on hold and then eventually cut me off. Sharks the lot of them!