Plusnet Sim not working in S7edge

[Angelamac]

I have a samsung 7edge that was previously my son's with an 02 sim. When he upgraded to a S9 he contacted  O2 to get the S7 handset unlocked so as I can put a sim of my own choice in which was my tesco sim, now I want to change to plusnet but doesn't work in this S7 and works in every other phone. I have contacted tesco and they say the phone is unlocked and so do O2. Any info in solving this problem would be very much appreciated.

[AndrewL]

@Angelamac: If you put the Tesco SIM in the S7 and used the unlock code provided by O2 then that will have locked the phone to Tesco. When you insert the Plusnet SIM, does it state that there is a network lock on the device? If so then Tesco are required to provide you with an unlock code, so I'd suggest contacting them again. If it helps, ask for a 'PUK code'.

[Angelamac]

Tesco said phone is unlocked so phoned plusnet again and tomorrow have to go back to tesco to request a (NUC) Network Unlock code or Network Unlock pin.

[Angelamac]

Still no further on in getting my plusnet SIM to work in my S7edge. Phoned tesco this morning and they said they can't give me a Network Unlock Code as the phone is showing up as unlocked on his system. So I guess it back to talking to plusnet again.