Hello @omar,
The issue with phone number validation during activation of free Azure account can be resolved by creating a support ticket and working with our Azure Subscription team.
To proceed further, I will need a few details from you. As this information contains Personally Identifiable Information (PII), please share the following details via private message:
Affected phone number
Contact email address
Please provide the above requested details over the Private Message so that I can proceed with creation of support ticket with Azure Subscription team and they will further assist you in resolving this issue.