iMessage and FaceTime Activation issue

Hi Team,

On July 16, 2024, I purchased an iPhone 15 Pro from Apple

Polaris Fashion Place store in Colombus, OH. The staff helped me to get some

applications replicated/copied to the new phone from iPhone 7 version. Since my

iPhone 7 was bit old, we could not completely perform the replication. The

iMessages and FaceTime applications did not work. At the end of July, I traveled back to Sri Lanka. I purchased an e-SIM from the service provider and all applications started

working except for iMessages and FaceTime. When you go through the settings

>> iMessage >> Send & Receive >> steps, it shows my phone

and Apple ID email address. But I only can select the email address not the

phone number. The system shows “Activation unsuccessful”.

I went through all remedies mentioned on Apple Support site

as well as all other sites. But, to my dismay, the error still exists. I also

removed FaceTime and reinstall, but error still exists.

Any Advice please.