Unauthorized hold on account lead to over draft charges.

I recently went to a government course out of state at a prominent hotel. I reserved my room with my personal checking account with explicit instructions not to place any charges or holds on the card because it was a debt card and there wasn't enough funds on it. Upon arrival I paid with my Government Travel card. The second day I was there, I checked my bank account and all my transactions on that day had over draft charges but my account showed there were sufficient funds available. I contacted my credit union, and they said there was a hold on my account for over $1,300, even though my account showed I had over $1,200 in my account, it didn't show any hold. I contacted the hotel immediately and they said the hold was placed on the account in error. They contacted my credit union and removed the hold, but the credit union refused to remove the $140 in over draft charges. On several occasions throughout the two weeks the hotel and myself tried to get the charges reversed. The credit union still refuses. I feel like the credit union has STOLEN from me. This is especially aggravating since there where sufficient funds available. This incident was the fault of the hotel, not I. I am filing a formal complaint with the National Credit Union Administration as well as the Federal Trade Commission. Are there any legal grounds for me to take action against the Credit Union?

The HOTEL would be my first try. They might pay your fees out of good will.