If I'm not wrong, when you create an EOS wallet, you set up a username, and if someone wants to send you some coins or tokens, that person needs your username. It could be that somebody is sending coins to someone whose username is very close to yours and that person is making a mistake. It's the only thing I can figure since the amount is too high for an airdrop.
I do not rule out possible mistakes. But I think by now, the sender should be aware his payments are going to a wrong address. It is not just a single transaction, but series of transactions. The OP can provide more visual details to back his claim and members can properly figure out what went wrong.