Hi Aishwarya,
Apologies for the delayed reply — I missed your previous email.
Thank you for your suggestion regarding replacing the number for testing purposes.
Before cancelling the current number, could we possibly try adding a new temporary number instead, while keeping the existing one active? This would allow us to compare the behavior between the old and new numbers and better understand whether the issue is related specifically to the current numbers or to Apple verification SMS delivery in general.
Please let me know if it would be possible to arrange such a test.
Thank you again for your assistance.