If you're serious about spending a lot on the cloud it's reasonable to expect a taste. Just like an ice cream store.

the free tier is for that, isn't it ?

You don't get much in terms of performance and capacity in the free tier preventing you from testing anything beyond the tiniest workloads.

If you need to pre-arrange expenses with the finance department, it's much faster to test drive with credits.

ah, i see. in that case i think it's okay that you should pay.

its not like ice cream.

if you messaged random people it's quite reasonable that they didn't bother answering you. i wouldn't have done it either.

you should get in contact with sales people via the proper channels and arrange testing (whether paid or not) with them.

If you message random "people that work at gcp" then "not caring" is probably one of the most polite things they could do.