Anon, thank you for your kind words. I am so sorry to hear about what your own experience has been. Sometimes one has to cut one’s losses. You still need to be respectful (as per kibud av in the torah, even when the Av or Em is not so nice), but you can do what you are doing and limit the interaction between you.
Have you tried to write them a letter expressing your hurt, giving examples of what they have done (i.e., mocking your daughter, which is a BIG thing in my eyes, more than if they mocked me)?