Xperia Z5 Compact not reading SIM Card

[noblexxj]

Hi to all,
I undertook a battery replacement and put a new charge port in while I was at it.
After putting the phone all back together and powered it up everything appears to work on the screen functions but the phone no longer reads the SIM card and only recognises my WIFI up close to the modem. This has rendered the phone unusable. I have tested the SIM in another phone and it is OK. I have removed and inserted the SIM several times and the phone recognises the SIM and does a restart but then does not read the SIM card once it has restarted and displays the message “No SIM card - Emergency calls only”. It is as if the SIM card reader is not working, but it worked OK before the battery replacement.
I spoke to a technician at my local shopping centre and he said he wears a wrist band with a wire connected to an alligator clip and connects it to an metal earth to eliminate static electricity in his body going through the phone and short circuiting it causing damage. Could this possibly what has happened to my phone as there was no mention about having the earth yourself while undertaking the battery replacement.

Could it be a faulty antenna as the phone now only detects wifi when it is next to the modem? Maybe overheated it with the heat gun to remove the back of the phone with the battery replacement.
Does anyone have an explanation or solution to my SIM card not reading?

Regards
noblexxj