It would also be nice to know how much of those 4.5 weeks depend on OPs handling of the issue:
video of problem and order number is not a big ask, it would be in my first email if it were to happen to me. Seems a bit of a clusterf-ck on both ends and it kinda sounds like OP bought this second hand and had to track down order number from the original owner: if it was my friend i would make sure i had the details from the get go, seems like the unit was delivered to another adress as no original box (if you live in the country side and have room for a grow but not for a box you may need?). It just seems like we havent heard the full story here, nor from op or mammoth.
Im sincerely sorry to OP if im wrong, and im glad he finally got a new unit.
Some of these "call out the manufacturer" threads are very valid, connectors burning out etc, actual danger. This one doesnt seem so clear to me if i try to be impartial. Maybe im biased cause i did some cust service with warranty, and id see all sorts of bad handling from both sides.