I bought a phone with cricket wireless last year and this year I decided to cancel the...

I bought a phone with cricket wireless last year and this year I decided to cancel the service. So I sold the phone not knowing I needed a sim pin code. I called cricket to have the phone unlocked because I sold the phone and the person I sold it to can not use the phone because of that. I feel this should have been told to me when I bought the phone and in that case I should have signed a contract with another company. Cricket wireless states on there web site that this is not contract with them but actually it is if you can not reuse the phone with another company because you are under a contract with cricket which they say it’s not a contract. I need the unlock pin for the phone I have sold to someone else.