Hi there- will try to keep this brief: my daughter saw our family dog collapse and haemorrhage and fit just before she died. This was about 5 years ago and she's never got over it. We then had another daughter, and have waited until she was old enough to go to school before thinking about getting another dog.
We were finally on this position in January and luckily found someone who was just about to breed her bitch. Not local, but only about 50 miles away. There was a lot of excited messaging back and forth to begin with, we filed out a questionnaire and she said we would be ideal. Scans sent etc.
Then around the due date she went quiet and stopped replying. My OH rang her, she said she was on the phone to the vet- puppies imminent!
Then she went silent again. I had a feeling, so I googled the breed/area- and there was the litter, listed at double the price on Pets4homes. We rang her and she feigned shock and surprise that someone had listed her puppies and asked us to email her the link.
Then nothing. Again. Finally I texted, begging her to just tell us what was going on: my eldest had walked in and seen the web page with the puppies and got really excited that they were here, and I had to tell her we weren't sure we were getting one any more. My daughter is on the spectrum and was devastated, particularly that I couldn't tell her what was happening.
Predictably enough of course we finally got a response to tell us there was no puppy.
(Sorry, I know this has turned into a vent...!)
So... how can we avid this happening again? We don't want a pedigree dog. We want a mutt, we like lurchers. We don't want to contribute to Covid profiteering by paying £2k plus (which seems average!), but we're happy to pay up to half that for the right dog.
I'd be really grateful for some advice or even commiserations. Feeling very low- I have never seen my daughter so sad, and obviously we regret ever telling her we were getting a pup. Now she wants this exact one, and I can't make that happen. 
Apologies for the very non-brief essay!