I thought i was getting 3 books for one credit but recieved a pm from the person saying she had to cancel because she could not find the books so ithought she cancelled everything but i recieved the book i ordered just not the free ones what would you do ?since the only reason i ordered from her was beccause of the 3 for 1 deal

I'd PM her, explain what you just said, and ask for your credit back. 

edited to add:  I'd also check her shelf.  Are the 2 books that she supposedly lost still there?  If yes, I'd be suspicious of a scam.

I am not sure there is anything you CAN do except be frustrated!    This happened to me once to and I felt as if I had been scamed.       There is no way to MAKE her send you the books and no way to ask for a credit back since you did get the book you paid a credit for.           She should have given you the option of cancelling the book when she didn't find the freebies.     I'm so sorry this happened to you.      

When she cancelled the order it went to the next person in FIFO who had the book so that's probably who sent it to you, and they had no connection with the 3for1 deal.  Check out who sent it to you and see if the name matches the person you originally ordered from.

ditto to Jessie, that happened to me and I was really thrown for a loop.  If she couldn't find the books she should have given you the option to cancel so it didn't go to the next in line

From the Help Center:

When a sender clicks cancel order on a transaction (if, for example, she can't find the book she agreed to send), the system will pass your request for the book automatically on to another member who is offering the same book (if there is another copy in the system).  It will do this without sending you an email notification.

• If a sender clicks Cancel Order
  • The request will cancel automatically, and will be passed along to another member offering a copy of the same book. 
    • the requestor will NOT get an email when this happens.
    • the requestor will be able to tell that the request has passed along because the request date will have changed.
      
  • If there is no other copy of the book available, the book will go back onto the requestor's Wish List and the requestor will get the credit back.
    
    • the requestor WILL get an email when this happens. 

If the sender told you that she couldn't send the book but there is still a request for the book on your account page:

• Click (personal message) on the transaction to see whose name pops up in the To: field of the empty Personal Message.
  
  • If it is NOT the same name as the member who told you that she couldn't send the book, then your request has been passed to another sender.
  
  
  • If it is the same name as the member who told you that she could not send the book, then the sender needs to cancel, or ask us (via feedback) to cancel (she cannot cancel if she has already marked the book mailed).

I'd PM back and ask for your credit back, explaining why.

I don't like using the Book Bazaar anymore because of things like that - last time I ordered a 5 for 2, the three 'freebies' were not postable at all and the sender didn't bother to even apologise when I PM'ed her.

Did it come from the same person you ordered the deal from?  If so, pming sounds like a good idea--but if it went to the next book in line, you're going to confuse the person who sent it to you.