Don’t use WhatsApp
The terms of service are the contract that WhatsApp are willing to make their service available under. You have 2 choices:
- accept those terms and use the service,
- reject the terms and don’t use the service.
There is a theoretical 3rd choice but it’s not practically feasible: negotiate with WhatsApp for your own custom terms. It’s not feasible because WhatsApp have to be willing to do that, and they aren’t for the very simple reason that they can’t administratively deal with individual contracts with millions of users.
You can’t accidentally agree to a contract. Entering a contract requires a deliberate intention by all parties.
WhatsApp showed their intention by providing the service and the terms. You showed your intention by clicking “I agree”. The instant you did that the contract became binding on both of you.
You can’t go back later and say “Whoops! I didn’t mean it.” You did it, you meant it. If it was a mistake it’s your mistake and you get the consequences of your mistake.