if the default code was not changed try 1234 OR 0000

i read the forum rules and i believe or i think my phone is locked, basicly when i turn on my phone it asks me for a 4 digit code. i had lost my i710 and i bought me an i205 for temporary use. turns out that after 3 weeks i found my i710 again but now i don't remember my code. can anyone help me? i went to a nextel store and they told me to take a 2 hour drive to another nextel store that they say "MIGHT" help me. well im under age and my mom will say no to driving that far off. so if anyone has a number i can call or a way i can get in to my phone plz help me