Just to keep you on track....
So far I managed to get confirmation from Hyperpro/Calsport.
They agreed I got faulty spring.
They say that this never hapened before.
They promised me new spring... weeks ago.
It should be delivered already, but they said:

"Just an update regarding your spring.
We had a delivery turn up late last week, but your spring wasn't present.
It should be on the next delivery due in 5 days."

That was 9 days ago, and no message update.
Hmmm.
I still have some faith.
Will let you know how it ended.