When I get issues were vendors point fingers at each other I three way call them, tell them what's up, hit mute, go get a coffee, and let them figure it out.
Oof. You should bill them for your time. I sent HP or Dell (can't recall) an invoice for $800 in my early 20s for my time wasted on a support call where a "support tech" had asked me to reinstall Windows as a way to fix a disk that failed in a RAID array. OS was AIX.
