BenzVince

I'm trying to troubleshoot on my remote key, that I have a 2003 E320 and I have only one key, lately my car won't unlock on the keyfob, so I had to unlock and lock manually, so I had the battery replace and it's not working, since last time I change the battery it was fine, but it wasn't long before it will not work, it works randomly though when I pull the door handle without the remote. My question is, what could it be, is the transponder has died or do i need to replace a new transponder? Cuz I have dropped my key a few times when I am opening my house door, and i accidentially dropped it.