phone number changed when sim card put in new phone

[Android Question]

I put my sim card from my old phone in my new samsung galaxy s3 and find that I can not be contacted on my old number, only on the new number which shows in my phone status. My sim card is a Tesco network sim on monthly contract.

 

[Rukbat]

Contact the carrier. It's possible that nothing can be done, but it doesn't hurt to ask.