TIL about 3D printing patented designs

Looking for advice on a legal issue. Here's what happened.

3D printing patented designs. I've been dealing with this for about 14 months now and the situation isn't improving.

This involves original creative work over the past 21 months. I do have documentation proving my ownership and timeline.

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

I've dealt with this before.

I had to go over their head/manager. It took 1-3 months but was worth it.

Not a lawyer, but I have direct experience with this.

What trips people up most is escalating to a supervisor/manager. I'd recommend following the formal complaint procedure instead.

Not surprised at all tbh.

The thing that gets people is having everything documented. I'd recommend keeping a detailed timeline instead.