Try just continuing to game the daughter as if nothing happened with the mother. As we know, if a parent tells their child not to do something, that's all they then want to do lol. For all we know the mother could just be bluffing and has actually said F-all to her daughter in the hope you'll just go down quietly.
If after messaging the daughter, the daughter says nothing about the thing with her mum, then I think you can relax and the mother was just bluffing. If the daughter messages you back saying her mum said not to speak to/that you aren't supposed to talk to you, I'd say something like "I'm not the kind of guy that will stop talking to someone I'm beginning to like just because someone else says 'I'm not allowed'. I've been enjoying getting to know you and intend to continue doing so." so something like that, if the mother sends you a message back you can just send the same message to her and swap out "you" for "your daughter".
You may have lost the battle but the war ain't over dude
