Home sale

Hi all this may seem a really silly question but , I part own a property with My ex partner (we are both on the deeds ) and we are selling due to seperation .
We put our property up for sale with an agent in Quesada (never again btw but that's another story) . We had an offer on the property my ex partner was willing to accept but I wasn't (and didn't) yet the estate agent still took a deposit from the buyer , they are now threatening me (and have been for the last 3 months ) with fines and court proceedings . I believe the estate agents are known for such tactics but their solicitor (a 2nd one they have now contacted me with the first went away when I explained the situation) is now threatening this also . Surely if I don't accept the offer they can't sell ?
Again I think it's a daft question as how can they sell something that belongs to me ? But as I mentioned they're threatening me with fines , court proceedings and all sort .
Tia for any advice

You should name and shame the estate agents so other people can give them a miss

I would suggest that you consult your own legal team