i dont know how to get rid of it
im guessing you mean roads,if so, im not certain there is a way you can remove them. if you are able to get rid of the road, you would still be left with a hole in the ground… 
Yeah that’s a real bummer. Always plan your roads before you build them. 
I did plan my road but when they placed it down they put it above ground
did you perhaps accidentally use the slab tool instead of the road tool?