If you're on the web version, there's a "Report a Problem" button in the bottom left of the screen right after you answered a question during a lesson. That gives you some option to file a report for the course moderators.
If you're on a mobile version, the flag icon on the banner that pops up after answering a question does the same.
I translated it as 'My mam is angry with my dad' It was marked as incorrect. I've contacted via the 'Report Flag'. That's what it's there for.
In Wales 'madre' is 'mam', not 'mom'. This is also the case in many parts of northern England, particularly in areas of what was once Lancashire (Merseyside, Greater Manchester, etc) and in Cumbria.
Also, 'madre / mamá' in the Welsh language is 'mam'. In Cardiff, the capital city of Wales, some of us say 'mama' too, but depending on the mood. You can learn Welsh with Duolingo. Give it a go! For those who know Italian, Spanish, Portuguese and French, the grammar rules are very much the same; we have masculine and feminine nouns.
My mother ... my father. Wrong?!?! In ENGLISH English no-one would say "mom". Would you have allowed "mum", or even "mam" which is what we say in the north of England? Too many times in this course, English English is scored wrong, when an ENGLISH speaker would never use US 'English' idioms.