What to do when family doesn't believe you?

I recently (as in 2 days ago) received a call from an aunt who said she got a disturbing phone call from grandma saying that she (gma) got a call from me stating that I was in desperate trouble and needed to borrow a lump of cash. Keep in mind I NEVER made this call and am not in trouble and do not desperately need cash. I returned the call back to the 3rd party accuser and my uncle answered, whom I thought I'd just clear it up with him, no worries. To my sad and absurd dismay, he did not believe me and proceeded to hang up on me. Its quite obvious that he is in denial of even the idea that the old age of my grandmother has token its toll, and that this accusation doesn't hold any weight.