I have recieved my iotas today. Then I have tried sending some iotas to bitfinex. The first time it works. The second time, it does not work despite many re-attach. I have launched again the light wallet and now it seems that all my iotas have disappeared !! Is someone know why ? What can I do ? Please help.
Most likely just some display problems, change nodes and see if the balance shows up again. You might also check your address(es) in the explorer, to see what's going on:
https://thetangle.org/