Lex can be...very persuasive with how he hires his staff. Amari and Levina got roped into quite a long term service, though...they aren't going to question it without an outside force making them. They've done this for years after all. It's all they remember...being good maid girls~ They have no reason to doubt anything...

Aka he hypnotized them into serving and made them think they've always been maids. At least he treats them right