They said they'd pay

My SOs parents said they would go halves on our pram with my parents if they wanted to. My parents agreed. I went out last week with my mum and I paid the almost £300 deposit on my pram. I told my SO and he said to let his mum know. So when she came round I told her I'd found the pram I want and had paid the deposit and set up a payment plan, when it would be delivered and showed her a pic etc. she didn't once ask how much it was costing or how often the payments had to be paid. I feel really cheeky mentioning that they said they'd go halves and don't seem to be but my parents cannot afford to pay the full price. I'm quite happy to go halves with them instead but it's annoyed me that I was told they would and now don't seem to be. His mum has done this a few times now. She said we should go for the house we wanted as she would help us by paying the extra £100 we'd need, which she hasn't. And she also said she would Buy my Moses basket, I told her it was limited stock and they are almost out and ended up having to buy it myself or I wouldn't have got it. I have no problem providing out own stuff for our baby but if I'm getting told it will be paid for by someone else and then isn't it's annoying. I didn't think I had o worry about a pram so concentrated on redecorating. Now I have both to pay for. And she wonders why I'm panicking about everything!