I do have proof of the transfer of 0.105 BTC from Bittrex to Yobit -

Address: 1CueV8QaA6gtsJB4xuVm6ntM3E2KjzftnS
TxId: 3164de375fd19e5c1e8bf7fc4ad60a467f52e5fdd9b33d80a82061ecc2885482

I have no record of anything that happened after that on Yobit because they've deleted the history. But surely this transaction detail will be enough to prove that Yobit received funds for me?  And I have all the emails from Yobit saying when I set up the account, and the when I've recently logged in.  I only have one account.

Yobit is a scam, they not only emptied my wallets but deleted all my history too - it looks like a brand new account!  I have proof of a transfer of 0.105 BTC from Bittrex to Yobit, and that was received on Yobit on 8th Jan.  I then used that to buy 10,000,000 PAC, and I then had a PAC balance of 10,000,000 and a BTC balance of 0.005 (or maybe a bit less due to the transaction fee).  But when I next logged in a month later, all balances are zero.  The worst thing though is that there is absolutely nothing in my history, no record of the deposit of the 0.105 BTC, no record of the purchase of 10,000,000 PAC.  There is no record of any activity ever in my account now, so it's either an honest mixup or outright theft.  Obviously I logged a support ticket but no response whatsoever.  I've also filed a report here just today, so anyone else having similar problems could try this - https://complaint.ic3.gov/default.aspx?#