I'm ready to give up too. I love to track data, but the truth is, I don't use any gas except on out of town trips that can be tracked by cellphone photos of the two screens. Anyway, sometimes even Voltstat's missed gasoline used.
Meanwhile, GM's "myvolt.com" is a random crap shoot. myvolt only tracked ~56% of the kwh I used in December, which is really bad compared to what it used to be. Myvolt also only tracked ~86% of the miles I drove in December. Anyway, I had fun tracking my 12 months of gen2 daily data since I purchased it last December. I used the odometer trip-a when Voltstats went down.
The Volt's a great car and I did get some fun data looking at kwh/mile and mpg variations and monthly variations for gen1 and gen2, but I'm done now ... After 3 or 4 or 5 re-authentications to voltstats, I'm done there too. I'm going to stick to mostly just driving now, which is also fun.