Whenever you are sending a coin and you don't know the chain which the receiver send to you, always try and ask the person for the chain and whenever yih are sending always be focused to avoid those kind of mistake, mostly the people that make this kind of mistake are the newbies that don't know anything about cryptocurrency, if you ask them to send wallet address, they always endup sending the wrong chain. I think we should be very careful whenever we are making transaction. Thanks!!!
It never just happens to newbies, such a mistake is also possible for an old user who is in the hurry to send and is not able to copy the address correctly. Remember that transactions are not reversible, in the case that it is sent to the wrong address it is likely we can't get it back. You're so lucky if someone will contact you and ask your address but that was rare as this receiver also does not know who sends them. And not even you know who is the holder of that wallet.