If you bought white sewer pipe that doesn't say "Schedule 40" or DWV; if it is that thin white stuff that is similar to the kind that has holes in it and used for french drains, then you should take it back and get some that at least says DWV.
Another way you can check is to see if it fits a DWV fitting such as a Wye or Tee.
And your clamps should have a piece of metal that covers the full length of the rubber cylinder.
If it is the right pipe, you will not be able to break it with the clamps.
You can cut the pipe with a chain cutter/snapper device, or you can cut it with an abrasive wheel on an angle grinder. I have also occasionally cut a piece with a very good and heavy duty saber saw. You could probably also do it with a SawZall. I would be more inclined to use a saw or grinder device near the concrete where the consequences of breaking the pipe into the floor are severe.