ってしまえばそれまで
to itte shimaeba soremade

Expression

1. it is certain true that ... (but); you can't argue that it's not ... (but)

「騙 だまされた」と ってしまえばそれまでですが、「うまい はなし」に った当人 とうにんであることは間違 まちがいありません。
"damasareta"to itte shimaeba soremadedesuga "umai hanashi"ni notta tōnindearu kotowa machigai arimasen.
If you say "I was tricked," well that's certainly so but there's no mistaking that you were the one who signed up on a "sweet deal".