Time won't set

I just received my new vtech LS6225-3 and can't set the time. I love this phone. Everything's working fine except for this one problem - which is driving me crazy. I set the time - it seems to work for about 2 hrs., then before you know it - it's behind 2 hrs. This is annoying, especially with caller ID, and my messages. I purchased this from Amazon and it's exactly 3 days old - return? But how can I reorder when it could happen again?