couple months ago my wifi on my 4s stopped working. It won't even give me the option of turning it on. Backups nor reset to factory has made it work. What can I do?

My 4s wifi feature has stopped working. It won't even let me have the option of turning it on or off. Then out of nowhere yesterday it worked most the day and through this morning but when I got back home it's right back to not even allowing it to come on period. It's like the slide bar is all white/greyed out..doesn't let you move it..I don't have any warranty anymore and I can't afford a new one yet. And I do have the most recent update.