S6 network issue

[Sharif]

For some odd reason the network on my dad's S6 is always pretty low or zero (Bar wise,also when calling it they seems to say it's off) though this is pretty normal precipitation in that particular area 

but zero reception has never happened,restarting seems to make a difference *I think maybe,not my phone*

 

Things

• The micro sim was slimed down to a nano sim by a blade (Not sure if this is the issue) 
• Hardware defect? 
• Some sort of support issue? 

 

Help really appreciated   (Unlocked model) 

 

[Sauron]

The phone could be defective, or maybe it's his service provider screwing up. The sim shouldn't affect this (it either works or it doesn't usually).