If you have lost, misplaced or for whatever other reason can no loner use your 2FA devices then you will need to recover access to your account. This is covered in more detail in the 2FA Account Recovery how-to guide.
Please use the reset password wizard.
On being invited you will sent an email by the Katapult system with a unique invite link. Clicking on this link will start the invite acceptance process. If you have not received this link then firstly please speak to the member of the organisation who invited you. They can resend a link if required. It is also worth checking your email accounts junk facility just in case the Katapult email has been put in there. If you still require help after trying all of the above then please reach out to our support team.