T-mobile Provided inaccurate plan information and was unable to activate the device. I have proves. internet

I looked up a plan on http://prepaid-phones.t-mobile.com/prepaid-plans and I got my sim card from Target to my existing phone.

The plan on line stated:

100 minutes talk | Unlimited text | First 5 GB at up to 4G speeds

Now get unlimited international texting from the U.S. to virtually anywhere included in your plan—at no extra charge.

This plan is only available for devices purchased from 
Wal-Mart or devices activated on T-Mobile.com

I understood that activating the divice on line would give me the plan. I tried activating the device but the site would redirct me without activating it. When contacted the customer service they would deny  the plane I wanted due  it is not Walmart device. I understoon that you can get the plan if you buy it from walmart "or" any device that you register on line.