You have already leave China. She will not able to distrub you if you don't contact her.
I don't like my mom too, for we have great difficulty in communication. It is not unique, a lot of people in different country sufferring in same trouble. so I am so happy I can live in Canada peacefully.
Besides, if she hurt her so much, you can sue her too. For she didn't need so much money to live in China's country ie CAD 300.
Good luck!
I guess this is a fake story. I don't believe you changed the monthly payment from 300RMB to 300CAD which is around 2100RMB. It's not a small amount in China. Even in Canada, 300CAD is not a small amount, especially for a new immigrant family. As her mother was always complaining her husband for his Mei Chu Xi, it seems her family doesn't have much income in Canada, assuming just doing Labour job. Yes, 300CAD is big. I don't believe it so much. That's only my comments.
母女不和的家庭,世界上究竟有多少?