Maybe you entered in the wrong website of MEW. There are many cloned website of myetherwallet that are scam. You should bookmark the real website of MEW which is
https://myetherwallet.com/ and secured. You can check list of ethereum scams here in database ,check their website:
https://etherscamdb.info/scams/This one should need to be consider by the people since there are so many fake MEW websites and he should properly check wherever they like to log in their private key unto that site. Ang people need to be more careful since eth is no dispute option if we been compromised by those damn guys around, And also we should careful on where we put our private keys.