I wish no one would use this argument again. Ever.
Here's an example:
What if I were to tell you that I believed that a magical pink elephant with wings lived in the centre of the earth. It could telepathically communicate with everyone on the planet, and even had the power to answer your prayers. Would you believe me? No? Why not? You can't prove that the elephant doesn't exist. Using this logic, there are a million things that you should believe in simply because they can't be dis proven. Goblins, unicorns, Zeus...you get my point.
The fact is is that no one (including atheists) can definitively disprove the existence of anything. That being said, we do have to look at these claims objectively and figure out the probability of said being existing based on evidence (or lack thereof), and just plain rationality and common sense.
While I'm on the subject, I'd also like to point out another flaw in your argument. The burden of proof rests on the shoulders of the person making the claim. Just as the burden would fall on me to prove the existence of the elephant, it also falls on you to prove the existence of your god. Neither I nor anyone else has any responsibility to disprove your claim.
I just had to get this one off my chest.
