Last Thursday I was trying to buy an odd lot size of SMH shares. My buy order was not getting filled and I didn't receive any message telling me what was going on. I contacted IB customer service and asked them what the problem was. The representative told me that some exchanges don't accept odd lot market orders so I should send a marketable limit. I changed my order to a marketable limit and it still did not execute. I didn't get any answer as to why I wasn't getting filled, so I went ahead and changed the order to an even lot and was filled immediately. I asked why I didn't get any kind of message as to why the original order was not filled and was told that IB didn't give an explanation message because it was sent as a GTC order and that was "illogical" anyway. I don't understand why that should matter? I then got an apparently stock message saying that other customers were waiting and my time was up. I asked if he could explain what the rules are on odd lots since it would save both myself and IB trouble in the future. I got the stock message again, and then the rep ended the chat session. I later found out from an ET member that odd lots are not allowed in the Holder ETF's. If the representative didn't know the answer to my question, I would have preferred he just admitted as much and let me know he would get back to me via email with an explanation. Instead he hung up on a customer who was being polite and asking a legitimate question. I know I'm a small fry and odd lot questions aren't big worries for IB, but I think customer service should treat customers with more respect than what I was shown.