How do i activate my new KPN simcard?

Hello! So last week I received my kpn sim, although they asked me couple of times on phone if I want to change my number or keep my Lycamobile number.. so I said to keep. Anyway they sent me a bunch of sms about confirmation 'yes' to number 6688 .. but I didnt have my credit and couldn't send the sms through my lyca number.. so when I received the sim I've got message that if I don't answer nothing I receive new number.. so the thing is how do I activate this new number if on the sim there was no new number and this is the second week when I have my kpn sim in my phone but I am not using it... Could anyone help since I don't want to waste anymore time and I want this fixed.. since I will be paying for nothing.