I got threatened to "get personal" with by my bf's mom.

[mimitchigotchi]

So... I refunded my roommate's partial rent payment for December. I told her that she needs to pay her half on her own. If she can't understand plain English when I tell her several times she is correct about calculations and wants to argue over nothing then I don't want anything to do with her portion. She said she'd make me pay half the power bill which is fine. She can pay half the water then I guess. Starting next month. I wanted it 50/50 to start and even have separate places in the kitchen for our food items. She weaseled her way out of it. I'm sick of it. 

What even IS getting personal? Some kinda slang I need to Google I guess since I'm not very up to par with the art of instigation.