Chances are, the contract is void. If you have an agent, ask them to go over the fax. If not, you can seek advice form an agent who services Potomac, MD and they can review the documents for you and give you an opinion.
I do service Potomac, and my office is in the heart of Potomac at River and Falls Roads. I will be in the office tomorrow if you would like I can take a look for you then.
Realtor & Internet Marketing Specialist
Serving Potomac Maryland, Montgomery County and surrounding areas in Maryland.