are you sure the caps are sealed tightly?
did you follow the apfelwein recipe to a T? didn't use a weaker yeast or added a lot more sugar?
the difference between 65 and 70 is a lot to yeast trying to force carb a bottle...maybe keep em warm in the house for 3-4 weeks and try again.
Primary: English Mild
On tap: Pale Ale, Lancelot's Wheat, English Brown Ale, Steam Beer, HoovNuts IPA
Bottled: MOAM, Braggot, Raspberry Melomel, Merlot, Apfelwein, Pyment, Sweet mead, Cabernet
Gal in 2009: 27, Gal in 2010: 34, Gal in 2011: 13, Gal in 2012: 10