Horrible

After calling to change our flight to an earlier date and we paid the penalty/ changing fee. We then go and cancel all our accommodation and tours for the days we will be missing and change our travel too (we moved our train tickets). After cancelling everything because we are going back earlier we get a call to say no the system was wrong and it will cost 700euro to fly back, this is AFTER we cancelled everything and the initial price of ~191euro was paid to move the ticket. We now have to book all new accommodation and get new train tickets which will cost is 500euros... so now we are 500euro out because of a system error??