I would use more reliable services like MtGox, CampBX, Coinbase, or a trusted seller on localbitcoins.
Read the thread. He used bitinstant, and he received the coins without any problems. He even received free foot massage here from their representative. The problem is that he was using an outdated client which is likely out of sync with the network, so it doesn't show the transaction. Ultimately, the problem is that bitcoins.com, apparently operated by one of your "reliable" services (tibanne, that is mtgox) is irresponsibly abandoning their website and leaving it with outdated information.
this is what i figured the problem was but the problem with that is there is no wallet.dat file in the client i downloaded. I meant to go to bitcoin.org but i guess i was just tired or something and went to bitcoins.com