[...]
Otherwise you can contact certain companies that offer help, but those aren't the ones that "own" BTC so to speak. Be wary of giving sensitive info out though, especially if it's a relatively unknown company.
Note that those companies are only responsible for the respective services they offer.
So for example if you deposited money at Coinbase and it doesn't show up in your account, contact Coinbase support.
If you have problem with a specific wallet, either browse the wallet's FAQ / documentation or look here:
https://bitcointalk.org/index.php?board=37.0If you're having general questions regarding Bitcoin or require technical support just post your questions here on this "Technical Support" board (or better yet: use the search function, either on Bitcointalk directly or by quering google like this: "problem i want to solve site:bitcointalk.org")
And to reiterate what the others posted above: Bitcoin has no owner, company or franchise so anyone pretending to be a Bitcoin support line ist most likely trying to scam you.