I am sad to say that the attorney you are presently using is inadequate for the job. Fire him, and get one who is actually experienced in landlord/tenant real estate law as well as contracts. Most lawyers are.
Yes I realize you most likely represented yourself--it was a mistake in this situation.
I suspect with an almost 10k claim, this was not small claims court, and therefore you were dealing with a no nonscense judge. There are rules (proceedure, evidence) that are very confusing and need be followed or you lose (as you found out).
I agree with Scott and others, you have a business and a complex one with many rules and regulations to follow, if you fail to heed one small rule you lose.
For example, you mentioned that the water bill was in your name and you had an agreement for her to pay her share. Was this laawful according to the laws of SC? (not your gut thought of what's fair). There are some things you can not contract away.
Perfect example is a pet deposit, a tenant wants to move in with a dog... ok you figure the dog might damage the property (reasonable right?) not here in Mass, it is unlawful for a property owner to charge a pet fee or any fee other than 1st last and security (with therare exception of a key fee) any other fee is a violation of the consumer protection statute and subjects the landlord to pay up to 3 times the tenants losses plus the tenants attorneys fees! So, get a real lawyer for the important stuff like the contracts the tenants sign and $9900 claims!