Straight to the point, I think that it is so rude and unacceptable to refuse your customers to use the restroom that has been it that store for years for customer use, over the last 6 + months your store for whatever reason shut it down. Employees say that it broken and corporate office won't fix it, so they tell customers that they have to go next door to the salvation army store in which they aren't a customer of and use there restroom, because they are considerate of their customers and provide a restroom. As I am sure you are aware its not mandatory for your very large company to provide this very small service to your customer. As I am sure that when your out shopping and need to use a restroom that most places are happy to accommodate their valued customer by providing one.
I will never ever shop a dollar tree or recommend anyone to go to one for this reason. That store is just filthy and the employees are so rude.