I would recommend getting all your factual evidence in place such as the officers badge numbers, the manager on duty's name and how long she/he has been working there, and depending on what state you are in police may or may not have the right to search your car without a warrant, so I would look into that, who called the police is a big concern too. If it was the manager their boned, if it was a staff member they were taught to do so by the manager and both people could lose their jobs.
Contact an attorney asap too! It is profiling and harassment. Since that store found nothing wrong they legally can't ban you and you my dear have a case that could get you a lot of grievance pay. An attorney will be able to guide you along the way much better cause they will know all the laws in your area. Oh, also since you, hopefully will be working with legal help they can request the loss and stolen accounts and records from the store to look into how often, what times and dates and what is being stolen from the store. This can prove that you are Innocent too as well as the tapes that have to be surrendered to legal teams to review.
I say, slaughter them! Also, I am sorry that they did that to you. The same thing happens to me when I go into the Great Wall Shopping Mall here in Kent, WA. I am followed everywhere by the shop keepers. It is really annoying and I even heard one of them say, "White people can't be trusted. They steal. Watch her." It sucks that profiling still happens to this day.
