If your fixed term contract has come to an end (e.g. 12 months or 24 months) but you have not called to cancel your contract, you will continue to be billed each month as before and will receive calls.
If you have phoned to cancel your contract, it is quite likely you will no longer be able to receive calls and will lose your number.
What you probably want to do instead is to switch/convert your SIM card from a contract (e.g. pay monthly) SIM to a Pay As You Go SIM in order to keep your number, continue to receive calls, and give you time to request a PAC to transfer your number, if you want, to a new provider.
If you have instructed to cancel the contract you should be able to change your mind and switch to PAYG if they have not yet actioned.
Alternatively, near the end of a fixed term contract is the best time to phone and ask for the best offers available and providers are usually able to price match anything you find from the same provider on sites such as uSwitch.
Whichever instructions I give to the provider, I usually remind them to do it in such a way that I incur no penalty charges for early cancellation etc. Good luck! 🤓
