Didn't receive games. How long before leaving negative feedback?

I searched the forums for an answer but didn't find one. I apologize if there's already a thread involving this issue.. Two games were shipped out on March 28th and it has been 16 days. Should I leave negative feedback now or wait some more? How long until the trades time out? If the trades time out, am I out of the games and the points? Thanks for any help that is provided!

PM the sellers to check on the games, be polite, and see if they have been shipped. If you don’t get a response or they say that they didn’t ship them leave negative feedback no later then the 20^th day. On the 21^st day the system times out the trades and leaves a default positive feedback. You will have you points refunded if you leave negative feedback. If they have shipped the games, you should still leave a negative at the 20th day if they didn't arrive, then when they arrive email feedback@goozex.com and have the feedback changed to positive.

Thank you very much. I'll PM the sellers now.

Update: Both users stated that they have tried sending out the games but were returned by USPS. I've received games before and haven't had this problem before. What could be causing this and how could I correct it?

You could go to the Post Office and ask them. Also, you may want to make sure your address is correct on you account, if you have a number or letter out of place it could cause some issues.  Did the sender hand write the address or use the label? Messy writing could cause a problem. Other then that, the Post Office may be able to help if there are other issues.