HTC EVO 4G :: Data Call Failure - Error 67

I returned my perfect working non-defective EVO last week because my friend has a better deal for the monthly cost. So I joined his family plan and returned mine.

Unfortunately, my new EVO are having some problems. My new one has mild light leakage below the menu button. The volume control button is a bit loose, its workable, but just not as sturdy as on my previous EVO. Occasionally it has text messages delay, which never occur on my previous EVO, Im not sure if its related to Sprint or the phone itself. The battery is not as good as the previous one. Even though I can definitely get through the day with 15 hours for each charge, but I got 20+ hours on my previous EVO. Maybe itll get better once I charged it a few more cycle, its not the biggest concern for me. My biggest concern is actually my own stupid mistake! When I was altering the settings for my phone, I accidentally press and tried to active the Hotspot option. From there one, Ive been receiving the Data Call Failure Error 67 message randomly. Sometimes I just dismiss the message and its fine, sometimes I cant use the 3G after dismissing it. Ive tried to update the profile; turn off the phone; pull the battery. Sometimes it works, sometimes dont..

I don't need the hotspot function and didnt sign up and pay the $30 for it. I really dont need it, I just press it by accident ONCE! Is there any cure with this? I dont want to receive the error message randomly. And I don't want the hotsopt feature! I dont want to call Sprint yet before any other possible remedy, its kind of my last resort. Ive read from some other places that they just tell you to do a hard/soft reset and it is not a guarantee that itll work.