If you are concerned about the company not providing the service and you have already paid them, then I would not sign anything and demand a refund, including complain to whatever agencies may regulate this company, including the BBB and Federal Trade Commission. Signing a one-sided agreement may only make getting your money back more difficult and if you have no mailing or street address, there is nothing you can do anyway. Seems very bad. Is there any way you can stop the payment with your bank or credit card? If this is a consumer purchase, you may be able to dispute this with your credit card company as long as it is within 60 days of the statement date. See the top link below, for letter #2.1, which you can send to your credit card company by certified mail, return receipt requested.
If you consider this company unethical and doubt that they'll actually provide you with the agreed service, then even the best contract with the appropriate enforcement mechanisms and remedies will only help set you up for what sounds like a necessary lawsuit against them for breach of that contract.
Your instincts about this company indicate that you're better off not working out a deal with them, but just getting your money back.
If there's no way to get the money back by stopping payment on a check or disputing it withyour credit card company, you need to consult a litigator about taking legal action.
Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.
I agree with the other answers. Don't sign anything else with these people. Your instinct is right. Have an attorney from a firm such as ours to review the contract. The problem is if their promises to perform haven't yet been broken, you'll have to see if they perform their obligations before you can demand your money back.