GGN Brabant

In September 2011 I went for Xray in Eindhoven and two months later i was billed for it. I rang Menzis my insurance and they informed me that this was covered. I have no proof of this phone call however. After this phone call I ignored a further bill believing it was covered. Then GGN sent out a final warning last November, but I was away on a business trip. They subsequently summons me to court when i did not pay the final bill, they had my email address and emailed me the summons. This really annoyed me as they could have emailed me the final warning when i wasn't responding to the mail in the post. I asked GGN this and all they said was "By law we don't have to email you". Why do they email a summons and not the final warning? I would have paid this straight away if this was the case.
What has further annoyed me is that their letter for the summons had an extra fine of 130 euros on top of the 99.70 euros for the bill. In the bill their was a signed page with the original bill of 99.70 euros the next page stated what I believed was a bill if I fought the case in court. This was in fact the charge for booking a date in court. Is this the correct method for booking courts dates and charging the plaintiff?
Could someone help me with some advice as what to do next. GGN keep insisting to pay the amount but i really think they are trying to bully me into paying this amount of money. Furthermore one person at GGN stated last week that I owed 250 euros and today they said I owed 350 euros. The person i talked to just said "that's the amount my colleague is wrong".
Their stories dont add up and up.