Per our data, Migros Mobile runs as a monthly contract, so you are not tied in long term. Migros Mobile uses the Swisscom network. If you are switching over price, you will find cheaper providers on the same network with identical coverage.
You can cancel through your Migros Mobile customer account, customer service, or at a Migros store with a mobile counter.
Number portability is free in Switzerland and usually takes 1 to 3 working days. Important: do not cancel yourself if you want to keep your number. Register the port with the new provider, who handles the cancellation. Anyone who cancels first loses the number.
These providers run on the same network but cost less. Coverage and 5G are identical, and the order follows price alone.