Talk... the best thing you can do is be open and have honest communication.  Ask if there's something different you can do to help your horse not lose shoes. Ask if there's another method of communication. Ask if he would like you to use someone else to tack the shoe back on, then ask for a referral! Ask if he would rather not do your horse. 

I think an important issue to resolve, however,  is the lost shoe issue in the first place.  Why is this happening? ASK.  Also,  maybe instead of talking about him to other clients,  talk TO him. 

After you've asked all the pertinent questions and still aren't getting what you want.  Research,  get referrals, and look at feet  other farriers have done. Do your homework. 

Good luck!

Change farriers! There are plenty of good ones out there. He might be a decent farrier, but communication makes him not so great. There are plenty of companies that make/sell good products, but have a bad rep due to customer service or long wait periods. I guarantee if you switch to someone who will communicate with you, you'll be wondering why you didn't make the move sooner! Your horse is losing shoes somehow, whose fault it is, is besides the point. The rght combo of decent work and communication will fix the problem, or make it less of a hassle and not missing races.

New farrier. You shouldn't be losing shoes that often. I had the same senario happen years ago. Farrier would come out and the next day, would be missing the same right front shoe. Every. Single. Time. After the 4th time that happened and countless times calling him to come back and put yet another shoe on, I switched. I never had an issue with the new farrier!

When I have a horse that pulls shoes often I talk to my farrier and see what he suggests. Some horses clip the insides of their legs, some clip their heels. Without proper communication to your farrier you will never resolve the issue. You have to let him know how your horse feels. Personally my old gelding that used to pull shoes had side clips on and he would rip his whole wall off. We figured out that you couldn't let his shoes over-hang as much bc he really got under himself and would just step on them and off the shoe would go. I switched farriers after a not so reliable one that would schedule me for 6 weeks then not show. He was good but I can't be waiting 8 weeks for a reset. With my new farrier he is there 5-6 weeks on the dot. No pulled shoes and now I don't even how to use any sort of clips to hold shoes on. Best thing I did was swtich farriers. 

Also, I always have a backup farrier available, actually many. People get busy and have lives too. You can't expect them to cater to your every move. Just make sure your backups are someone you trust.