how can i fix snapchat????

I have a galaxy s3. the other day i went to open the app my camera screen is black. i can open snapchats i can watch stories but i cant take pictures or videos, if i try to it freezes and tells me snapchat is not responding. I have deleted the app restarted my phone and redownloaded the app but it doesnt work. i have gone through my settings to see if needed to fix one but nothing.. i dont know what to do at this point.