Dad's refusing to sign the contract?

So I found an amazing flat with my friend for 2nd year, it's absolutely perfect for us. We paid the 120 holding fee and she emailed across the contract,
My mom read through it and said it didn't make sense therefore my Dad wasn't going to sign it (He's my guarantor)
It's something to do with the fact that they're asking for 350 deposit but it's not in the contract so my mother is making a huge fuss about it =S
What do I do ? I really don't want to lose this accommodation

They tried to ring the letting agent like four times but we think she's on holiday because there's been no response =/

If there's an issue with the contract, then your parents are probably not right to sign it. I would go to the letting agent in person, and explain your parents' issues with the contract and ask them to explain. It may be a simple misunderstanding, or it may not be, and the agent may need to alter their contract.

Is the £350 being asked for by the letting agent or the landlord?

It references clauses that aren't there and it doesn't explain clearly about payment dates...
My mum emailed asking her for a correct contract that all fit and she hasn't replied.
The thing with the £350 is that the letting agent wants it (it's not the deposit because that's paid in August) but it's not on the contract, or on the application form or anything
My parents have asked for it in writing (they're a bit fussy with keeping track of everything they spend) but she hasn't replied =/

I want to go in to speak to her in person but my dad isn't visiting me until the end of the month so would she be prepared to wait that long?

They tried to ring the letting agent like four times but we think she's on holiday because there's been no response =/