I bought my iphone about half a year ago and now there art e a few problems. for example, there are little white dots under the screen, they look like grains of sand but how could sane get under te screen? and it seems the screen is loose, like if i push on it (not hard at all) it will sink in. and the trim around the screen seems loose too, like if i hold my iphone firm enough it will make a sound as if something were moving. How can i fix some all/some of these problems? thanks in advance 