Hello,
I can help you with this. I am guessing you upgraded from WHMCS 6 to 7. What PHP and ioncube versions do you have on that server? If you want to migrate it to the new server it will cost $250, we can try to fix existing installation see what went wrong after the upgrade and bring it back up, we can probably do it within an hour thus we would work at our hourly rate of $75/h to fix existing installation.