Getting nursery deposit back

Not sure if anyone knows where I stand on this. I had a baby this year and in January paid a £100 deposit to secure a nursery place for her for this Sept. Since then the nursery chain has been bought be a larger chain. I've had no formal notification of this and the fees have gone up significantly (over £10 a day).
As a result I have been forced to find alternative care as I'm a single parent and just can't afford £53 a day.
I emailed the nursery and requested a refund as in my mind they have changed the terms of the agreement but they've come back to say it's a non refundable deposit. Can I argue it?