Tesco are not 48's network provider.
Three are 48's network provider.
They also happen to be Tesco's too.
If your number ported to Tesco then you must have used Tesco's number porting process
and not 48's.
In which case you need to deal with Tesco and ask them about porting your number from them to 48.
48 can't do anything about numbers that were incorrectly ported to another provider so there's no point in contacting them about this.
While you're here, check out our "Featured Topics" below.
Our Troubleshooting Guide and Knowledgebase contain help and support articles and popular questions to help you as a 48 customer.