Join Date: May 2005
Location: Near Lichfield, UK
Programs: BMI DC Gold, BA Gold, LH SEN, Priority Club Platinum, Nectar purple
Posts: 949
Sorry, but your ticket is obviously a non refundable, non changeable one. The benefit of this is that they are very cheap, the downside, as you've found out, is that they cannot be changed, or if they can, are prohibitively expensive.
I'm guessing that the fee is higher than your original ticket because they are effectively cancelling your first ticket and giving you a new one.
Did you look at the fare rules when you bought the ticket? I've never used Vayama but most of the sites like Expedia/Opodo etc have a link that shows you the rules.