My inventory is empty/all my inventory has dissapeared.

That is server-side latency. If you faced that problem, just try to wait for a couple of minutes.

My EXP doesn't progress/my level has dropped to 0.

This may happen if your profile didn't loaded properly. If it happens to you try to change nickname. Also you should have level indicator("[1]" for example) beside your nickname while in game, that indicates that your profile loaded properly. Anyway this issue will be fixed.

My game crashes or did not work.

Try to erase game's cash (see below). If it doesn't help - without closing the game, copy and send to us your Unity Web Player log reports (see below) to the following email: b3dfacebooksupp@gmail.com.
Zip this folder using 7-zip or another archivator and send the file to email above.
Attention! Send the zipped file and describe the problem. Email messages without crash report files will not be read!

Can't buy anything.

Make sure that you have enough gold coins and stable Internet connection. As well as it can be the server-side latency.

Can't join the team in the game.

Make sure that team you want to join is not full.