Can someone bypass 2FA?

[Gener4lPurpose]

Is it possible for someone to bypass 2FA and if so, why would it be my fault that I can't dispute a transaction due to account being compromised?

I thought that 2FA was a secure system, not sure why I'm to blame if it's not.

Also worried about updating my credit card details on the system as I am not getting an answer as to whether paypal's security is up to scratch.