Chances are that you have lost that number at this stage.
But you might want to contact your old carrier and ask them if it's still available to you.
https://community.48.ie/t5/The-Knowledgebase/Getting-Started-Move-Your-Number/ta-p/53100
"If your old network SIM has no service or you cant receive the security code SMS then you'll need to make contact with your old provider as they'll have visibility of your old account."
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