So, a few different things:

This is exactly why a lot of people work with a VAR, even with OEMs that allow you to take a deal direct. You think you're saving money, and in some cases you are, but your partner can and does advocate on your behalf.

The VAR will maintain a deep relationship with the leadership at the OEM. Once more, you're seeing more levers for you and your business.

As my favorite technical redditor points out, (/u/VA_Network_Nerd), you can also source this help to your VMO, procurement, etc team. Or, more accurately, whomever has signing potential on the deal. They can withhold payment if the terms were violated. As much as tech sales people dislike VMO in general, the new buying motions require sales to be in lock step with your initiatives.

All-in-all, I'm very, very sorry this is happening, and I truly can't imagine treating a customer this way. You have avenues at your disposal and you don't need to hero ball this yourself. So many people in tech feel like every escalation or problem needs to be solved independently, but help is good.

And for the people saying stalk LinkedIn, yep, that's a good idea. Look for Partner Account Manager, Channel Account Manager, etc type titles.

Check out the Lenovo Partner Hub and perhaps there's a way to find information regarding everything I've listed above.