I regularly visit Dubai and I have had two suspicious experiences with this particular exchange companys branch in Al Karama. One of those experiences took place this past saturday at 6:30pm.Before I explain todays incident, I want to highlight a previous incident in February. I went to them to exchange $100 and I had already calculated the amount of dirhams I should receive. I noticed the cashier gave me 50aed less. So I asked for a receipt and at that point he said he made a mistake and gave me the missing 50aed.This past saturday, I attempted to exchange $100. They attempted to give me a hand written receipt. I refused and asked for a printed receipt and the manager approached me and asked for my passport and informed me that if I want a receipt of my transaction then I must present my passport. He was dismissive and told me to leave. I asked for my USD back and left.I believe, based on two separate incidents, that they are not an honest business and suspect they are behaving in a very unethical manner.The manager on duty there was extremely rude, shoo-ing me away with his hands in a very dismissive and condescending manner.