Take it from me, as someone who just finished their A levels. Do NOT study a subject you don't want to study. Based on the other two subjects you've taken it doesn't seem like you're a STEM student anyway and you may be a lot happier studying another humanity instead. You've said yourself that you're hating maths right now and if you continue to force yourself to study it for the next two years, things are only going to get much more difficult and worse. A levels are no joke, make sure you're studying what you want to, or in two years time you'll look back and regret it, I know I did.
I wouldn't encourage lying to your parents, but from your situation it sounds like they're extremely stubborn and won't give in. If that's the case just go in school and switch to a different subject anyway without them knowing until it's too late. They may be angry at you, but ultimately they won't be able to do anything and it'll be better for you in the end if you really don't want to study maths.
The college I went to allowed us to switch subjects in the first year up until the end of September. You may still have some time left, so I would highly recommend you speak to the head of your sixth form or whoever else could help you, sincerely explain to them your situation and just tell them you really would not like to study maths. At this point in the year they should still allow you to swap subjects, you may have to do a bit of catch up, but that's better than studying something you don'w want to for two years.