help me help me please

i have a big problem.... i am doing a tile job in 2 bathrooms and when i removed the toilet, the medal ring was all rotted.... well when i went to remove it with the flange(which should have came out of the pipe coming up through the drain) well,,, it didn't ... someone had abs glued the flange to the drain pipe... and it's concrete floors.... so we tried to cut the top of the flange to see where the abs pipes joined and we made a big mess.... Is there a way to fix the drain coming up through the floor? because I am going to have to cut it straight across to get a clean cut. i'm hoping that they have some kind of coupler to extend another opening for a new flange to fit on the drain.... i sure hope you can understand what i'm trying to say.... or do you need pictures? lol....

What size is the pipe?

Pictures would be great.

Can you tell us if the plastic body of the broken flange piece fits INSIDE the main pipe, or fit OUTSIDE the pipe. This can be removed; where it is located will determine how easy it is.

All ABS pipes are glue-fitted, so you do not have anything unusual here. In fact, the rusted metal flange is not unusual. It is the norm!