Do I still get my kids if I can’t pay the full child support?

My ex won’t let me see my kids because I’m late on child support. In our divorce decree, I have partial custody of the kids and she’s supposed to drop them off to me on Fridays. Since my work cut my hours back due to Covid, I’m making a lot less and having trouble paying the full child support. I pay what I can but she’s still refusing to bring the kids to me. She has done this before and I want it to stop. The lawyer I had during my divorce told me custody and child support have nothing to do with each other, and that I should get my time with my kids regardless. Is this true and what do I need to do to force her to abide by the custody schedule?