According to my standpoint, you don't want to mind this matter too.Although I think your friend is wrong, I think your aring affirmative also is wrong, otherwise why don't your friend believe you?So you should want your own mistake first.After, you again toward your friend explain know.I believe your friend certainly believe yours.
In my personal view, you do not need to care it too much. Although i consider your friend is not right, i believe that you also did something wrong, or why didn't your friend believe you? Thus you sho...