Hi.. I have a unlocked iPhone 4.. I plan on using it for t-Mobile.. So I called and they told me I can't use a "Monthly Plan" and that I would need a two year contract.. But I went ahead a ordered a pre-paid sim and I have a sim cutter.. I was wondering how I can activate it? Would I need a different IMEI number? I am confused. I want to use the $70 a month plan... http://prepaid-phones.t-mobile.com/prepaid-plans ^^Details. Please help.