Paul (Cell_Man) is a victim of his own success. He is typically very busy and gets many emails and pm's. Emailing him at firstname.lastname@example.org
is definitely the best way. Sometimes he does miss messages but if you follow up he'll usually get back to you ok.
If you send nasty/rude etc emails bagging him out for not getting back to you then don't expect a response- I know that we all expect people to get back to us within half a nanosecond of sending an email but he is pretty much a one man show. He does have good procucts and I've heard good reports about his batteries.
There are other places to get batteries and group buys seem to be reasonably regular if a little risky at times. TBH, I don't know who else I'd go to for a built battery pack- I have a home made laptop lithium pack and the next one will either be a Hobbyking lipo pack or Cellman A123.