Dear Customer, thank you for using our service. I would like to assist you today. Responses may have a short delay for review and research.
It sounds like you have a claim for wrongful withholding from the security deposit (you can file a suit in small claims court for breach of contract to recover).
For a good breakdown of the Security Deposit laws in South Carolina, see this link: http://www.nolo.com/legal-encyclopedia/south-carolina-security-deposits-36231.html
This will cover the carpet cleaning dispute, the frivolous cleaning costs, and the dispute over the doors that were damaged when you first took possession.
To vacate a tenancy in South Carolina, you must give your landlord 7 days notice (you need to do this in writing, and it needs to be an actual 7 day notice - a 2 month window is not the same as a 7 day notice), so you need to review what you provided to your landlord, and determine when you gave your landlord notice and when that would terminate your tenancy.
If your lease was not automatically renewing, and you never signed the renewal, you are correct, you would not automatically be bound by the new lease, you would be considered a "holdover tenant" or a "tenant at sufferance" (also called "month to month") so either you or the landlord could terminate the lease with 7 days notice to the other.
Once you determine the proper notice period, you can determine whether or not your landlord's withholding for rent should be included in your wrongful withholding claim or not (you can always include it and let the court sort it out, but I would recommend figuring this out yourself first, so that you have a better idea of what to expect going in).
Short of filing a lawsuit, you can try to mediate the dispute with them - contact your local bar association and request referrals to mediators, a third party neutral can often help you reach a mutually agreeable resolution. Use the bar association's referrals to contact a mediator or two, the mediator will then contact the other party to set up a mediation session, and you can go from there - hopefully resulting in a formal or written settlement agreement, and save yourself the time and expense of litigation.