Was your old service with another carrier Active?
You CAN’T port/transfer over to PM if you cancelled you old service with another carrier.
If this is the case, you need to pick a new number unless your old carrier was Telus or Koodo then you can port your old number over by contacting a CS_Agent to help you.
@quyetnguyen are you transferring from landline or mobile phone?
If is from landline or VoIP provider, it could take as many as 5 to 10 business days
If it is from Mobile provider, did you reply YES to a text from your old provider? You might have missed the step and hence porting was not completed
There is a number to call to talk to live support, they can re-trigger the process for you. I will message the number to you via the Community inbox ( https://productioncommunity.publicmobile.ca/t5/notes/privatenotespage ) . Check the envelope icon on top right. Call them and get it fixed