Did these shops try another authentic original Samsung Brick and Charging cord @good-life21 ?
Also check the charging port does not have any debris in it via using a torch.
A Samsung Experience Store / Samsung Service Centre can check your phone and advise if a repair if necessary is covered under the limited 2 year manufacturing warranty.
I'd suggest to only use a Samsung repair option as they'll use original parts and your manufacturing warranty won't be voided.
Daily Driver > Samsung Galaxy s²² Ultra 256Gb in Phantom Black.
The advice I offer is my own and does not represent Samsung’s position.
I'm here to help. " This is the way. "