privacy – Whatsapp terms and conditions

So I’ve been using whatsapp for a couple of years now, and for the past 8 or 9 months I’ve been ignoring their new terms and conditions by just clicking them away, no issues at all.

Today, I accidently put my finger on the wrong position on my screen and before I knew it, I had accepted the new terms and conditions. Is there any way for me to reverse this decision?

This led me to the a bigger question. What if a friend uses your phone, goes to whatever site and accepts all the cookies? Is a cellphone really that tightly linked to a person?