1- front camera, when I use it, shows everything rainbow-like. Everything is colorful. There's no filters, and applying filters doesn't help it. Soinds like a software or hardware issue, are you using any 3rd party camera apps... If not then it is probally hardware related..
2- The back camera is fine, but recently photos aren't being saved, and its getting quite irritating.. When you reported it isnt saving what is the camera doing, does it read a error when taking photo? Try going to camera / Menu / Reset to Default also same question as first question, are you using a 3rd party app?
Thanks for posting. Have you done a master reset on your phone and tried to duplicate the camera errors? If so, can you please PM me your mobile telephone number so I can research your account and see what kind of options we have for you? Thanks.