Christine Quinnhas responded to her estranged husband’s divorce petition — and what she’s accusing him of isn’t pretty. In documents obtained by RadarOnline.com, the former Selling Sunset siren is demanding primary custody of their child, alleging her ex, Christian Dumontet, failed to pay off a six-figure bill from the toddler’s birth, which she said has messed with her credit. As this outlet reported, Quinn and Dumontet are locked in a nasty divorce battle after she obtained a temporary restraining order against him following an explosive fight that allegedly involved their son. In the latest…