Sorry to hear that, but the thing is: only blockchain.info can help you out. They're a private company providing free online wallets, so if they mess up, the only ones that can help you is them... so you can either wait untill they fix their problems, or you can contact their support.

If you have $45k in BTC, i'd strongly suggest purchasing a hardware wallet like a trezor or a ledger nano S to store your funds instead of a free online wallet. This advice doesn't help you right now, but i hope it'll help you once blockchain.info resolves their problem.

BTW: there is a very reasonable chance it's just a backend problem at blockchain.info, so there is a really big chance you're not being robbed and your funds will re-appear in a couple of hours/days... But since i'm not a blockchain.info employee, there is no way i can say this for sure... I can just give you some input based on previous posts from people having problems with blockchain.info's wallets.