The other thing interesting here, people rarely comparison shop pharmacies on price in the USA. If the insurance decides not to cover something people just assume the cash price is reasonable and what they need to pay. PS: if you are price sensitive, Costco and Walmart are better options than CVS/Walgreens.
This is a huge problem! If they are in the US most insurers allow you to go straight to a specialist. Unsure if that helps them but for anyone reading this, if you can, go straight to a sleep specialist. My treatment was delayed for 3 years because I didn’t snore (another common reason for rejection of a sleep study).