Phone not allowed

I purchased a phone of music magpie for my partner to use, the phone is unlocked as I’ve used my sky sim and her EE sim in the phone now she has bought a new phone I’ve take the iPhone for my self but now the phone is not showing any signal from my sky sim and saying phone not allowed, my sky sim works in the iPhone 11 that she purchased and heR Ee works in both phones, I have proof that the phone is unlocked.

what should I do? I’ve followed online step and nothing as come of it.

TIA

CAMERON