I'd like to share my experience with them.
Today I placed a bet on an event, the odd was 2.13. After some time, I see that the same bet that had the mentioned odd, had now a 1.68 odd.
I opened live chat and explained my situation, even shared proof of how the odd STILL WAS 2.13, but I just received the generic "odds are subject to change" bullshit. I guess if the bet wins, I'll just win less.
Here I share some proof:

As you can see, the odd shown by Vave.com is @2.13, but to the right my bet has now odd @1.68. Funnily enough, after I opened live chat and mentioned this, the odd was correctly set at @1.68, just confirming their system is just fucked up and I'm just the victim of it.
https://ibb.co/TqNPvdLm
STAY AWAY FROM VAVE.COM