Tried to get a refund on a comfort class upgrade after my flight had been cancelled, but no centre in uk so you have to go through Holland which is not easy. As a result tried to get the refund when passing though amtserdam airport on a subsequent flight, but service desk there wasnt interested and when i tried to phone the customer service line at amsterdam airport still couldnt get through!
Also tried to transfer the upgrade on my next martinair flight to no avail, check in desk refused to do anything and said i had to go through customer service! I will not be flying with martinair again!
My husband has also had problems, when writing to customer service to complain about a recent cancelled flight and poor consequent transfer, the reply he had was 'we will respond in 6 weeks'! - Just not good enough!