Patching and Plastering - Spackle over sealant?

My window frame needed to be trimmed to make room for kitchen cabinets. The Contractor did a poor job of the trim & then filled it in with a sealant that dried rubbery. It is not sandable & doesnt "flow" with the window frame. I have been picking at the sealant with needle-nose pliers. Can I start spackling over the sealant? Will the spackle adhere to it? Thanks MUCH/Jina

It sounds like your contrractor used a silicone or latex based caulk to seal around the window. This is an acceptable and common practice. A flexible caulk is used to make sure the seal doesn't fail with house movement.
Can you tell us exactly where the caulk is located? Is it between the casing and the jamb? Unless the caulk bead is gross (more than 1/4" maybe) I don't see why it would be a problem. Can I ask why you would want to spackle over the caulk?

Hi-The spot where the sealant is, is not near the window jam. It is on the outer frame of the window. He cut into the frame to fit my kitchen cabinet, but when he filled in the sealant, it didnt go flush with the frame, ie: you can see a space between the sealant & window frame. I removed most of the sealant & plan to fill it in with spackle so I can sand it flush & paint it so it looks new again. Jina