Very very bad service

I ordered a Iphone 12 on the 9th of January by revibe through the PayJustNow App . It came the 13 of January. When the phone arrived it was faulty (Back camera lense can not focus ). I Raise a claim the 14th of January the second day the phone arrived . Im still waiting on a courier to collect it . And Thursday the 22nd its is already day 10 since I raise my claim . The 16th which was Friday I got a notification that the courier is ( in transit ) but still today im waiting for a courier to come and collect the faulty device. What must I do ?. No communication from revibe . I wrote emails to them and not replying to my mails . As they say you must return the device in the next 10 days you received it. Tomorrow (22nd January) its day 10 already. What must i do ? Because after 10 days I cannot send the phone back