Your SIM may still be displaying the temporary number EE use activate the SIM before they port your number onto the SIM.
Please process the below to remove the temporary number from messages, calls and iMessage -
Settings/ Phone/My Number - change the number if necessary to the one you require.
Then: Settings / Messages / Receive At - check that the phone number displayed is the one you require.
Finally: Settings / Messages / iMessage - turn off and then on again to complete activation.
If this still hasn't resolved the issue, please call 0333 202 5000 and we can raise directly with the network.