While I do like your reaction (you're open about your failures... I don't think you're actively trying to screw anyone here on purpose), I also think that you cannot offer a service and get paid for it while you don't know the language enough.
I'm a web developer. The equivalent would be if I sold a service for creating websites BEFORE I actually learned how to properly do it.
The right way to go would be to first learn to translate properly, and THEN - once you're able to deliver hq content translations - charge for it.
Practice a bit, maybe offer free translations until you're good enough to satisfy customers. Otherwise, intended or not, it's plain fraud. Simple as that.
Thanks for your advice, I understand what you've said. Actually I also get some works who PM me. That's why I have two proofreaders who are also my trusted friends, who checks, edit/revise my translation or if we are available, we discuss it thru social media platform (I upload it to Google docs or Google sheets, where we have access to edit and discuss it).
Because my goal is not just to learn but also to provide better quality.