You need to contact the carrier to issue you a new unlock code. Usually, the PIN/unlock code can be obtained through PUK. When you are asked to enter the CODE, the PUK should solve this issue. However, if there is no way to request the PUK, then contacting the carrier from where the SIM card was bought, is absolutely necessary. There is no way to crack the PIN unless you want to void the warranty. Keep in mind that this is a free service offered by the carrier.