pls help on nokia 3300 :(

[DonJohn]

i bought 4 units of this model from geeks.com and they have a qwerty keyboard, the guys say it is locked to ( Mobile Service Provider: AT&T Wireless, Cingular Wireless, CorrComm, LLC,.... EDGE Wireless (Affiliate of AT & T Wireless Network) , when i put my sim it turns on all fine except there is no signal, i tried a couple of uk online services to unlock but codes didnt work, gave me 'code error', do they need hardware unlock? i am listing below the details of a unit, i'd love to see your helpful suggestions.

IMEI: <removed>

Thank you.