The Bell bus website indicates that it will resume service on November 15, 2014 between Don Muang airport and Pattaya.
I last used this Bell service on 31 Oct 2012 from Don Muang to Pattaya, but it was a Bell minibus that provided pickup at Don Muang then dropped you off at to Suvarnabhumi (about 50 min), where you took the regular Bell bus to Pattaya. Looking at the 12:00 and 17:00 pickup times at Don Muang, this might be the same setup. Back in 2012, Bell did not require advance payment with the booking, and I ended waiting for over an hour for two no shows passengers.
https://www.belltravelservice.com/pages/PageHome.aspx Pattaya to Don Muang Airport & Don Muang Airport to Pattaya will start on November 15, 2014 Pattaya - Don Muang (06:30 / 13:30) boarding at Bell Pattaya Office
Don Muang - Pattaya (12:00 / 17:00) meeting at Seating area near Gate No 2
Fare: THB 400 / person (No Pick-up or Drop-off service)
!!! Accept only advance bookings !!!