Unhappy client

A colleague recommended Phonetradr to me as he had previously sold his phone through them and i subscribed through to their website on the 25th of January 2024.. They were quick to send The Courier Guy to fetch my new Galaxy S21 Ultra 5G at the office and they listed it on the 29th of January 2024..I lowered the selling price with the hope that it will be sold quicker but to this day it is still listed. I have been trying to get a hold of them vial calls, email, whatsapp with no success.. I even when to Rivonia where their office used to be and i was told they moved. I just want them to cancel my listing and return my phone