AIBU to expect my mum to help?

[Peppin]

My mum is a teacher (retired). She makes a living these days doing private tutoring of kids who need extra help with school work and for 11+, 13+ exams. I work full time and the DCs go to my parents' house after school (which is the local primary school).

I've asked my mum to help DS with some homework while he is at her house, as he is not a self-starter by a long stretch. I get home at 7.30pm which is too late to start doing homework. It's only one day a week he needs to do this work, and my mum agreed to help as it is her area of expertise. That was 6 weeks ago and since then on every occasion it's been "the day", she has not done it with him and says it is his fault as he does not want to do it/it was too hot/he went out to play/etc. The whole point is that I need her help because he doesn't want to do it on his own.

Today I rang to see if she was doing it with him and she said no he's gone out to play and then accused me of "hounding" her about it and hung up.

To avoid drip-feeding, I should probably add that my mum has the DCs after school rather than them going to a CM because when they did go to a CM, she kept insisting that she wanted to do it, they'd be happier at her house, etc. They are indeed much happier at her house than at the CM. Also I pay her several hundred pounds per month to have them after school, so it's not the case that she'd rather not be looking after them or is doing me a favour by doing so. I cannot reduce my hours/get home earlier because I am a single parent needing to pay the bills and my job entails these hours. I cannot change job either.

AIBU to be pissed off that she isn't doing what she said she would?

I think you have had fantastic advice on this thread apart from some very strange judgy comments early on, nothing to add except that I think YANBU to expect support from your own mother. Paid or not, part of a mother's role in your life as I see it is to feel your pain and try and do what she can about it, and if that means taking a DGS in hand (in an area in which she has professional expertise and experience no less) then out of love for her own flesh and blood she should jolly well do it with everything she's got. So on that score alone I think she's not doing well. Whether you're paying her or whether your DS is old enough or whether your ex is shirking his responsibilities is not the issue here. You asked your mother for help which she can reasonably give, and she's letting you down big time.

I hope you've managed to think things through and come up with some solutions that you are satisfied with.