I am so sorry to hear that you are having issues with your WIFI. I know how important it is to be able to utilize your WIFI to save data on your plan. In order to make sure you are getting the best WIFI signal for your device. Is your device on the current software version? You can check the software version by going into settings, general, software update. Your verison should be 6.1.4, if it is showing different. Please follow the steps to update your software on the device. Once this is completed test to make sure your device WIFI is now acting correctly.
Follow us on Twitter @VZWSupport
I believe this may be a new issue with the iPhone 4s
I contacted service desk and they advised to reinstall software.
Believe it is a hardware issue, waiting on my new phone to arrive today
Don't know if this is your problem but a You Tube video from the Apple Support Forum is here: