[Skunkworks] Unlock Huawei E1750 "Only the specified SIM/USIM card can be used on the device"

Hi Skunks, I want to Unlock my Huawei mobile broadband, Model E1750, I have got the unlock code but when I put a different SIM instead of prompting me for the code, this is what I get "Only the specified SIM/USIM card can be used on the device" What do I do to unlock it Thanks Liwindi