Photography / Image Rights - company using my music without sync license

Has anyone dealt with something like this? I'm not sure what my options are.

company using my music without sync license. I've been dealing with this for about 5 weeks now and the situation isn't improving.

This involves software/code I developed over the past 6 months. I do have documentation proving my ownership and timeline.

Do I have a strong case? What should my next steps be?

I work in this industry and unfortunately this is very common. The good news is that when people actually push back with legal representation, companies usually settle.