Not able to activate my mobile number for facetime and imessage

I’m using a VI (vodafone idea) sim and trying to activate FaceTime and iMessage on my iPhone 15 plus. My iOS is 18.0.1 which is the latest iOS. I spoke with apple support and they said that I need to have some talk-time balance in my sim as my carrier (VI) will charge me for SMS while trying to activate. I did add around ₹20 talk time balance in my sim and then I was advised to turn FaceTime & iMessage off, restart my iPhone and then turn iMessage and facetime on. Post which, my mobile number will be activated in 24 hours. However, my mobile number is still not activated. It’s been almost a year that I have not been able to use my mobile number for FaceTime and iMessage. Need some genuine support as this is not good experience with my iPhone.