Opodo Refused to honour terms an conditions on my ticket internet, Internet

I bought a ticket with Opodo and before purchasing I checked the condions carefully. I was supposed to be able to cancel or change my ticket with a small penalty. I even wrote to the airline and got a reply confirming the same details. When I asked Opodo (10p a minute calls with numerous pauses and 'technical delays') they first confirmed the change fee, then suddenly changed their mind and told me that I would loose all my money if I cancelled or changed my flight. When I mentioned the terms and conditions I had read on their site before purchase they refused to enter into further discussions, simply kept repeating that I couldn't change the ticket.