I can't say too much about Diaflow yet. When I bought the deal, my tier was not added successfully, so I was stuck with the free 500 credits.
I contacted customer support, and it took the team 10 days to reply.
It took another month for them to fix my tier. That's already most of my possible refund time.
I started to build an automation, but quickly ran into a roadblock, because their system always sends API strings instead of JSON, but unfortunately, I need a specific format to communicate with BreezeDoc. I've been waiting for five days now, after asking the team for help. By the time they reply, my refund window will have probably closed already.
So I may get the refund before it's too late, because the customer service is the absolute worst.