This is exactly what happened to me during Covid... I had a flight that got cancelled at the beginning of the pandemic since the country closed the orders (essentially). A year after, still on lock downs and et al, I wanted to enquire about a refund, for months I got not answer, until I caught wind that people using Twitter were actually getting results. Now, I don’t use social media at all, so I had to create a Twitter account, twit about my case et voila! 30 mins after I got a response and they send me a PM with a case number... Not even going to mention the airline, but it is infuriating...

I can't imagine them sending it to collections. What kind of recourse would a company like Vercel have if you don't pay it?

They can sue you for the bill plus the legal costs.