NET10 changed from 4G to 3G- WHY?

Does anyone know why Net10 has changed my service from 4G to 3G? I have an iPhone 4S and I've been using Net10 for about seven months. I have one of their SIM cards that you can put into any phone of your choice and I'm on the $50 4G unlimited monthly plan. This morning I got a notice on my iPhone that there were new carrier settings available and it asked me if I wanted to update so I did. Now my phone says it is using 3G instead of 4G when it had always been using 4G. I would really like to know why this happened and if I can change it because I'm paying for 4G service, not 3G.

Added (1). I fail to understand why you felt the need to waste your time by leaving a rude comment.

I fail to understand why you are asking here instead of asking Net10.

The iPhone 4S does not have a 4G antenna and can not connect to 4G, it's only 2G and 3G. The iPhone 5 was the first iPhone with 4G.

iPhone 4S specs:
http://www.gsmarena.com/apple_iphone_4s-4212.php

Your service with Net10 can be updated, changed or suspended at anytime. There is a clause in the Net10 service contract that states that they can do this to your service. As soon as you activate your phone, you are saying that you understand and agree to the Net10 service contract.

Net10 does not guarantee data speeds with any of their plans.

You may want to go to the Net10 Facebook page and ask why this happened to your phone and if you can change it back.