In case you cannot find a way to the MBBS college prediction tool you have already bought, here is a very straightforward, professional way to solve your problem:

Use the same account you have registered before you made a purchase; it will give you an entry based on your profile.

Make sure that you have not lost your session-when the site loses your session, sometimes the site will come back when you log out and log in again.

You may not want to see how to clear your browser cache but want to use a different browser/device, in case your cookies are blocking your access.

Start contacting the support and sending them payment receipts and information about your account as soon as possible- they would be able to unlock your access or give you a direct link