Did the phone repair shop rip me off?

[totallysane]

Hi, so my I gave my S6 Edge to my dad.
Battery stopped charging so he gave it to a phone repair shop (lol idk why he didn't come to me, but nevermind.)

The guy at the store said he would change the battery, and see if that was a problem. Turns out that it would still cap at a certain percentage.

So he then claimed he would "change the motherboard." ..for £60, when the part alone is £60 on eBay? Is this a genuine fix?

After my dad gave in the phone, I googled the problems and they suggested cleaning the cache etc (may I add I wiped the phone like twice before.)

This is where it gets interesting. I know how to root and stuff. When the phone was given in, it had the stock Samsung Firmware installed. Now that I've gotten the phone back, it's come back with O2 apps installed. The guy at the shop did not install this himself as there is no Google account linked to the phone, so you can't get into the Play Store.

In addition to this, a SecurityLogAgent notif has come up. "Unauthorised actions have been detected. Restart your device.."

Did this guy just flash an O2 version of Android 7.0?

Is there any way to view a log of what was done to the phone's software?

He's giving me a 'week' to see if there aren't any problems.

*edit* - so I installed an APK that outlines the phones info, and yeah he flashed an O2 variant lol.
Camera is not working so I'll be going back to sort that **** out
But is there anyway at all to see if he changed the motherboard?

 

[Rukbat]

It looks as if, in an effort to save your dad some money, he replaces the motherboard with one from a "not fixable" phone he had lying around. (A lot of shops will keep phones that, say, have smashed screens and don't pay to fix, or are left because the owner doesn't want to pay as much as was asked [I used to do that in my stores - we had a cabinet full of Nokia screens].)

Since it's a Samsung, try flashing the stock ROM (see [Samsung] How to flash Stock ROM via ODIN if you don't know how - aside from waiting 15 minutes after the flash - the phone will seem to be dead - it's trivial and boring), and see if that gets it back up and running. If not, bring it back.

The only way to see if he changed it is to compare the original IMEI to the one in the phone now. If they're the same, he didn't. If they're different, he did. (He can flash a different firmware, but most shops don't know how to change the IMEI.)