As above, Direct Consular Filing - which is what your profile says, and would also explain how you got an interview so quickly.
If you aren't DCF then I think your interview may have been scheduled in error as it was much quicker than normal, so that may be why it was cancelled (when they realised their mistake). It's usually much longer than 3 months for a 'normal' case.
For contacting them to enquire, here are their details. https://ais.usvisa-info.com/en-CA/iv/information/contact_us
Good luck.