Ok, so you, the business owner, wanted a website, and went with provab, who agreed to build your website in 10 days for $1400, $400 of which was an upfront payment, agreed to, and signed by you, or your representitive. Provab were given 2 days by you on the project, before you decided, because of what appears to be cold feet, and lack of satisfaction with the design presented, decided to cease the project. Therefore somehow you have decided that what was provided to you only amounts to $100 value, and want your $300 dollars back.
From what you have provided i dont believe they have breached their contract, and therefore are entitled to the agreed upon and signed downpayment amount of $400.
Mind you, let this be a lesson “you get what you pay for“
Sorry.