If the amount is not large enough to hire a lawyer, you can still contact your state attorney general, department of commerce, or whatever other government agency that regulates banks and retirement plans in your state. It sounds like you need to gather proof from the 401k (like a copy of the canceled check, or transaction details of any wire transfer) and then go back to the new IRA bank. You might even contact whatever local news channel does "8 on your side" or whatever they call their consumer news and help segments.
Also note: you may be told that in order to do this kind of rollover, it must be completed within 60 days. And if you do get a check reissued, or the new bank finds the money, they may tell you that it is still do late to do a rollover. While the 60 day rule is generally true, there is a procedure to request a waiver for cause, such as a bank error. So if the money is found, you should still be able to treat it as a rollover.
