Customs delay from China. How long should I reasonably wait?

At this point I’m not going name any names but I have been waiting for a shipment from China that has been held by US Customs for eleven days now. The distributor has been very responsive to my concerns and has tried to obtain information from FedEx and customs broker without much luck. He’s telling me the package was picked randomly by customs for inspection but to have it held for eleven days seems a long time for just an inspection. Something tells me there’s more to this than just an inspection that’s holding it up. 
When I purchased this unit I was assured it would be shipped promptly and wasn’t expecting to have to deal with the uncertainty and BS I’m experiencing now. Just wondering how long of a wait is reasonable before I throw the towel in and demand my money back?