I had forgotten my cet user id

you could try to retrieve your user ID and password from google chrome. click on settings followed by passwords.

this only works if you had saved the password and user ID on your computer.

Once registered successfully, you would have recieved your application number and user Id on your provided phone number and email Id.I would suggest you to check there.If this doesn't help you will have to contact the KCET authorities:
keauthority-ka@nic.in

Helpline numbers:
080-23-460-460 (9:30 am to 6 pm ; except for the holidays)

I hope this helps.