I’m not sure how we can help you. Are you over watering? This is the number one way most new growers have seeds not come up.
How are you germinating them, what is your process, this is ‘grow support’ and we’d need more info to be able to give an informed response.
If you need help about your order, or the seed guarantee, you have to do it through the e-mail only, be patient, there is likely a huge time difference in the Netherlands and the office is not open on the weekends.
Contact them there.
Happy growing,
~MacG