That's interesting. I have no seed words for my webwallet. Only json key. Do we receive seed words when we create an account on webwallet beside the json key?

Yes, when you create a new wallet, you receive a 24 words secret phrase that you need to store.

You 100% had to have the words when you made the wallet, because there was a screen where you had to enter some in order to proceed, they are the most important thing you have in terms of non custodial wallets and should be kept safe at all times. They are your recovery method

you should create a new wallet, migrate everything you have there and keep the seedphrase safe