I am sorry to read that your prepaid sim was blocked, ​@shahram-m. I understand this was due to not having used your phone number for more than 6 months, and then not topping up your credit within the following 3 months. We will always send you messages when the expiration date of your prepaid credit is nearing. In these texts we will also inform you about what you can do to keep your phone number. Unless you have blocked KPN, there is no reason why you should not receive these texts.
Regardless, we cannot retrieve your phone number. It is lost. The only solution is to order a new prepaid sim.
I also understand you would like to know how you can prevent this from happening in the future. You are to use your prepaid sim once every 6 months. To be save, I'd recommend using it once every 5 months. You use your prepaid sim when you send out a text message or place a phone call. Using a little data also helps.