Few problems with phone calls

Hey, so today I was on a call and another call came in. I ended the first call and took the second call. When I went to hang up the second call the "end call" button" was just a gray box with nothing in it and I had to wait for it to disconnect itself. A little later I was on Facebook and a call came in and I hit ignore but then the page/app was frozen and I had to close it. Anyone else have this issue before?