If you have Alexa controlling blinds through Vera scenes, then you must have the Vera Smart Skill added to Alexa's Smart Home capabilities. And that's fine ... it does work and is relatively easy to set up, but as I mentioned before, I was disappointed in the several second lag between my voice command and the action. I already had the HA Bridge installed and set up, so I stayed with it.
As for "open" and "close" commands not working, Alexa waffled back and forth on this a few times in the past several months. Initially "open" was equivalent to "turn on", and "close" was equivalent to "turn off". And that was great! (Note that folks in the UK often use "open the kitchen light", so it made sense. But then Alexa started tightening things down, thinking that "open" and "close" would be used to control locks (like your front door) and they didn't want to support that (for security reasons). At least that's my hunch of why they stopped supporting open/close. Yet, a few weeks after they stopped supporting the open/close as equivalent to turn on/off, they reverted to supporting open/close again. And then back to not supported yet again. It's stayed not supported for some months now. Pity.
So anyway, I currently have scenes for my blinds so that I can "Alexa, turn on living room blinds" to close then, "Alexa, turn off living room blinds" to open them, and "Alexa, turn on (or off) living room blinds halfway" to set them to their 50% position. It was so much nicer to be able to say "Alexa, open living room blinds" (for example), but Alexa won't let you do that anymore.
IMO, Alexa's settings should allow a configurable checkbox for us to specifically tell it that "I want to allow open/close as equivalent to turn on/turn off, and I accept the security risk of doing so".
Greg