Syncasso 是个什么存在？

本人2年前在荷兰交换，去年下半年开始，一个叫Syncasso的机构频发给我发邮件，大意是让我还90欧元。
在我印象里，我没欠谁的钱，房租都是提前一个月交的，不可能有欠费。
求问这是个什么机构，是不是诈骗的？真的不胜其扰。

Syncasso is an offical outstanding money collection authorities. Basically you have an outstanding or overdue invoice and the company can not find you. After that Syncasso takes over your case and keep chasing you. If you read the letter carefully, you woud understand.