Bill M.

1. The first leg of a 2-leg flight was changed, needing me to change the second leg. Both legs originally gotten through Vayama.

2. It's a telling sign that it's very hard to find even their pubic phone number. Go try to find it. Anywhere.
But finding it is worthless._Every time_ I was on hold so long (over 45 minutes) that the call was disconnected.

3. I was desperate since this change in times would make me miss my second leg, get me in late, and blow the whole reason for my trip.

4. Desperate, I finally found another number to call: *******777
If you're dumb enough to use Vayama, then use that number.
Oh, and their customer service email isn't useful either--surprise! Instead use: vayama [at] travix.freshdesk.com
(You'll notice that that isn't a "good" email: It's not much of a real company, you see.)

5. Even using that "secret" phone number and email, it took so long to try to fix things through them that I would have literally missed my flight if I kept trying.

6. Luckily, the airline I got a ticket for (Cathay Pacific) themselves helped me book a flight on a different (non-affiliate) airline to help me out.

Let me restate this:
Vayama was a HUGE problem and of NO help. I had to finally beg the airline to act as my booking agent for another airline!

Tl; dr
Sure, if you never have anything ever go wrong with your flights, maybe consider Vayama. But THEY WILL SCREW YOU if anything goes wrong at all.

Had delivery issues with a smart phone I ordered, but Everbuying resolved it with a refund.