Do I have to pay for a mobile subscription that my number has been moved from?

You are responsible for terminating the subscription and you may be financially responsible for a subscription, even though your phone number is not linked to the subscription. According to the Telecom Advisors’ code of conduct (under point 8), your previous operator should terminate the subscription when the number is transferred. Note that any notice period begins at the time of the transfer, unless you have terminated the subscription earlier.