An arrogant employee should not prevent anyone from dealing with any large chain store or any store for that matter. It is usually preferable to complain directly to the manager, after all the store or franchise does not belong to that cocky, smart @#@ employee. It happened to me before and I found that the best way to deal with such situations is to circumvent the troublesome salesperson. Usually, it works and if not just go to the head-office and be frank with them, they will listen because they are just people like you.
They will probably have a nice little chat with the culprit and I bet that the employee will usually swallow his overflowing arrogance and change his ways.