Hi Fizzy_B,
Apologies for the late reply. We are sorry that the sim card has not resolved this issue. Unfortunately, there is nothing more we can do to get this situation rectified.
I have triple checked and had two other colleagues check your to make sure 100% your handset is now un-blacklisted which it is. We have tried your mobile number and it is ringing out, if this was blocked on the network it would go straight to voicemail or you would get the non-obtainable tone. We have checked everything, and as the SIM works in different phones, we know it’s not the network as we can't block a SIM against a certain phone.
We have googled it and there may be a problem with the handset. Unfortunately, as this is a 3rd party handset, we are not able to offer you advice on how to get this resolved, we can only suggest searching on how to fix a pixel 6 pro that wont recognise a sim card.
Kind regards Jodi.