Most of these companies are scams (that last guy barely got his Credit EMT license). The FTC has reviewed these sort of claims and never once found a company that can actually back them up. No one can guarantee they'll be able to fix your credit. So when I say that I fix credit ratings for a living, the first difference between me and those liars is that I absolutely don't guarantee any results ... which isn't to say I don't lie; I just don't lie to my clients. My entire job is lying -- to credit card companies, debt collectors, banks -- all in the name of improving people's credit scores. Or trying, anyway.
"No, sir. I'm not going to lie to your wife 'just while I'm at it' ... that costs extra."
First, some quick background that everyone should be aware of: Your credit score isn't set in stone. It changes constantly and depends on your past and current payment history. While the cheapest, most guaranteed way to restore your credit is by making a long-term pattern of good financial decisions and paying off your debts, that can take a long time and most of us usually ruin our credit if left to our own devices. So, you can dispute certain claims on your credit report directly to the credit agencies, or you can work with your creditors to get them to reduce your payments.