As I mentioned in my previous response, I would need specific examples of what’s happening at your end to better help you. Whether or not you charge sales tax depends on your business nexus:
There’s more on this here. If you do not have a nexus, generally, there is no sales tax. However, each state may have different shipping tax regulations. When it comes to Florida, shipping is not taxable if it is listed on a separate line in the invoice:
All the best, Hyde.