Water has a very high heat capacity and because of the tilt, the Earth would have remained warm. Tilting the earth 70 degrees gives large parts of each hemisphere 24 hours of sunlight for three months. Twenty-four hours of sunlight for three months on water does not get as hot, but also never cools below the freezing point of ocean water. The Snowball Earth problem is different but has the same solution. During the Proterozoic 2.5 billion to 544 million years ago, evidence exists for glaciation at the equator.
Researchers suggest that total global glaciation occurred three different times.
To suggest that life made it through really hard times three times is really hard for me to believe. The global climate model for this period uses an Earth with somewhat more land mass, the 70- degree tilt and shows glaciation occurring at the equators, while the poles remain ice free. This scenario, in which some ocean and land remain unfrozen, would allow species to survive the equatorial glaciations. Although a collision can be cited as the source of the 70-degree tilt, the question of what untilted the planet remains, because today's tilt is about 23 degrees from vertical. At the end of the Precambrian, most of the Earth's land mass was centered around the South Pole.