I do some freelance work on peopleperhour.com

I've built a site for a client according to their spec, I had to make a couple of small changes to make it work properly and more secure, adding functionality that wasn't in the spec but also makes the site better. The client is extremely tech illiterate and wants it his built his insecure way...which I have relented to and offered to do but he submitted a request to refund his deposit of £1200 ( 50% of the total is held in escrow by peopleperhour.com )

For me to dispute this I had to pay a non refundable £120 to peopleperhour.com which is pretty insane but I paid it any way as I had no response from their customer support in 3 days ( now 4 ) as you only have 72 hours to either accept the refund request or dispute it.

The dispute was resolved quickly by pph in my favour but the client has now submitted another refund request meaning I now have to pay another £120 to dispute the refund which is ridiculous and this can seemingly go on forever with no risk to the client.

In four days I've received no response from their customer support despite assurances from their twitter account.

What can I do?