Vox - please collect your router and do your job!

I cancelled my dads Vox subscription last year April - it was an early cancellation and have paid them the full amount outstanding excluding the router which they advised would be collected from me and credit from the account. I have been waiting since May 2022 for them to collect and keep receiving final demands from a collection agency for the outstanding amount!! They just aren't collecting the router and when I ask if I can rather drop it off with them, I get told that clients aren't allowed to drop anything off at their depo! I have liased with the rep I initally dealt with and he keeps telling me he will follow up but we are no closer to a solution or a credit. Come on Vox!! You guys need to jack up your customer service! Furthermore, you guys are quick to send an outstanding account to the collections agency but not very quick to do the job you're supposed to do. This issue needs to be sorted out urgently!!