I have been stocking a 220g over the course of the last year, and have had to rely on internet vendors for 95% of my fish. I would take a look at the vendor feedback forum on this site, search on the name of any vendor you may consider before you purchase. It won’t be hard to figure out who to trust, and who to stay away from, at least not for the names that come up most often.
After a year of doing this, divers den is my go to source. There have been issues, but they never hesitate to make it right, 100% of the time.
No matter where you get fish, use a qt process - proactive or observation - and take advantage of the R2r disease forum if you run into anything that gives you cause for concern. Great bunch of folks over there!