Wi-Fi won't turn on problem

[Bcn2k]

So I have a Galaxy Note 3 that my sister gave me a couple days ago. Day 1, the Wi-Fi was working perfectly fine. Day 2, It turns off and on continuously for no reason. Day 3, it refuses to turn on at all. Like, It's not that it won't connect to any internet options, It's that the Wi-Fi swtich stays greyed out, and won't turn on. So I tried a multitude of 'solutions' that the internet provided, and heres what I did.
-Factory resets (5 in total)
-Gentle taps on the back
-Power cycle (including take out battery when phone's on)
-Airplane mode, turn on, turn off airplane mode (Still didn't turn on)
-Hotspot on and off
-Switched off Wi-Fi scanning
-*#0011# and turn off Wi-Fi power saving mode
-Called Samsung and T-Mobile (My carrier), and both had no solution
-Take out SD Card
-Clear Wi-Fi caches

I will not send this phone back for repair because I know nothing is wrong with it. 3 years prior to the day my sister gave it to me, she has never ever had this problem before. This problem only came to be when I inherited it. If you have a solution, please tell..

 

[anon(238680)]

What did you change after you received the phone?
Do you know the wifi where you're living works?
Did you change any settings?

FWIW, a 3 year old phone is subject to failure, you could just be unlucky in that the wifi unit just rolled over and died. That could be reinforced by the erratic behavior the day prior to not doing anything.

 

[anon(238680)]

Posted for the OP who wasn't able to post and sent me a PM:

I changed absolutely nothing
-The Wi-Fi I use is working. I use in for everything else that requires it
-I did not

 

[anon(238680)]

From another thread, this error seems to be fairly common around the Android world:

As you've already covered pretty much all the fixes I found, try Turn off phone and remove and replace sim reboot, check wifi.