[NC] - Landlord refusing to return security deposit

Here's the situation: Renting in North Carolina, our lease ends on May 31st. We bought a house last month and moved out early April, but she would not allow us to break the lease, so we agreed to fulfill the remainder of the lease payments through the end of May. In the middle of April (last month), our landlord informed us our security deposit is not going to be refunded. She claims that a stipulation on one of the lease pages which says "Lease deposit is Non-refundable. No additional charges will be given to tenant" means that she doesn't have to return our security deposit. She has not provided any reasoning related to damages, but claimed she always retains the entire security deposit from tenants to prepare the house for the next rental listing.

I have argued that this is not legal and that unless she can provide proof of legitimate damages that aren't wear & tear, we are entitled our full security deposit back. I am planning to inform her that because she is acting in bad faith and we have in writing her intent to not return our security deposit, we will not be paying our full final month rent. Our rent has gone up by $200 since moving in, so we will pay her the $200 difference, but not the remaining amount that is equal to our security deposit. Should I place the remaining amount we are withholding in an escrow account in case she comes after us in court?