How can I reverse a Bitcoin transaction mistakenly sent to the wrong address?
Firstly, Bitcoin Cash is not Bitcoin. Secondly, neither Bitcoin nor Bitcoin Cash have any sort of central authority or way to reverse/refund transactions. This is completely intentional - all confirmed transactions are final. The only way you can get a "refund" is to ask the person that you sent the Bitcoin Cash to to send it back to you. If you don't know who you sent it to or how to contact them, then unfortunately your money is gone.

The whole point of cryptocurrencies like Bitcoin and Bitcoin Cash is that it is like digital cash - once you hand someone cash in person, there's no way to get your money back except by talking to that person and asking them (or forcing them) to give you your money back. If you have no way to contact that person, then your money is gone.