The Letting Centre

We (4 of us) found a flat through an agency, and paid the holding deposit, agreeing a move-in date of 26th Feb. The agency conducted reference checks and we got together the deposit and first months rent. In the week leading up to the 26th we repeatedly tried to contact the letting agent to organise getting the keys and siging the lease etc, but were told the agent was sick and no-one else could help. We were eventually told nothing could be done until the day of the 26th, when the agent would be back in the office. On the 26th (move-in day) we were told that we couldn't move in as the current tenants were refusing to move out. It transpires that someone at the agency did know this (prior to the 26th) but did not let us know. We had packed up all our belongings, taken days off work to move, and had found new tenants for our current rooms. We are now stuck in limbo as we have nowhere to move into, but have to move out of our current places.
Have any other tenants found themselves in similar situations? Can we get any reimbursement from the agency (e.g. our holding deposit, costs of getting the bankers draft, having to pay for temporary accommodation etc) for the massive inconvienence this has caused us? We are starting the process of going through the agency internal complaints procedure, but I would like to hear if anyone else has been in a similar situation.