You are not playing it right. When Sonya does her Cartwheel and you blocked it, you can D1 her first before she can D1 you back. Also, you need to watch Sonya's meter because she can Ex Cartwheel through your D1 mashing. Fishing for Sonya's Cartwheel depends on your spacing especially on wake up, you can cross over so it will whiff OR you can step right outside sweep distance and NJP combo punish her Cartwheel. Players especially here are making Sonya's Ex Cartwheel so overrated crying out for a nerf or remove armor, it's ridiculous. Online Sonya is a nightmare, I will admit that. Those things that Death was trying in those tournaments on stream got Sonya's Cartwheel blown up, it's not good as people think. Good players know when to use Ex Cartwheel effectively, online scrubby players abuse Ex Cartwheel like no tomorrow.
Don't you play Kitana? She can perfectly fish for Sonya's Cartwheel up close and zoning. Kitana can even punish Sonya's Dive Kick (all angles) with 2,1,Ex Fan/Fan Lift even online but you need quick reactions.