How do I Block purchases

Unfortunately, there is no way to block purchases at this time.  You could try contacting customer service to see if you could get a refund but the likely hood of getting a refund for 2 movies would be slim.  Sorry, I couldn't be more helpful.

There is no way to block purchases on DirecTV Stream, setting parental controls will only block ratings. Restricting purchases is a feature for the satellite service, but for some reason NOT on the stream service. I can't tell you how many times I've had to explain this to DirecTV agents... But I will say that every time I've called I've had all charges refunded once they finally understood. 

It seems like a really simple feature, crazy it hasn't been implemented yet. As someone who cares for a loved one with Alzheimer's/dementia it's a HUGE accessibility issue.

If those rentals are not viewed--you can get a refund:

" Current customers may obtain a refund within 30 days for unviewed rental/60 days for purchased titles"

This is the most ridiculous thing that DIRECTV Stream has. All other services have a way, to limit these things.