I work for Leslie's in SoCal. I hope this helps:
1. Shoes are a very common part when it comes to PVU and Nav., so in the middle of summer when vac repairs are at their highest, stores will run out. Even when kept very well stocked, there are times when we run out for a few days in the chaos of summer time, considering PVU's and Nav's are the most commonly brought in for repairs. So if we happen to get hit with a a few more than expected (which can be up to 15 a week depending on the store), then we have to either get a store transfer set up, or just sit back and wait for our next truck delivery. Which could be another week (or two during fall and winter) depending on when you go in. Even with a store transfer, if another Leslie's employee can't bring the item or pick it up, then it needs to be sent via FedEx, which is an extra cost. So if you order a part through us, and don't want to pay shipping, then don't expect it to be in any time soon. Our regular shipments aren't exactly as regular as say, Ralph's or Target. Even with a standard 4.95 ground shipping, depending on the availability of the item in our Distribution center(s), it could take longer if you're ordering a high demand product (i.e. - Intex "A" filters, at least for my area). Shoes would be a quick thing, but just so you know, in the middle of summer, we do our best, but with only a handful of employees per store, and the customer volume that most of our stores tend to have...well, bad things happen :/
2. In regards to the CYA comment, I'm not sure if you were asking if 40-90ppm in a salt pool is ok or not, but no worries. That's fine. I usually say 50-80, but a little above or a little below isn't a problem. Where you wanna watch out is if you're using stabilized tablets and Chlor-Brite on a regular basis. A good chunk of Chlor-Brite is CYA, so if you're not careful with your initial CYA dosage, then over the course of a few years (give or take) you'll end up with an abundance of CYA in the water. This CAN, not will, but CAN lead to chlorine lock, which is a lack of oxidation to the chlorine, therefore preventing it from working properly. This is a huge debate topic, but from my personal experience, I've seen it happen as low as 115ppm. Typical I just say that the danger zone is 120ppm+. Not everyone experiences it. As long as you're showing chlorine and holding it, then don't worry about it. Otherwise you can do a partial drain, or try breaking the lock, which I won't bother going into since I just realized how off topic I'm getting!
Anyway, I hope that helped at least a little. Sadly, Leslie's (as with any company) will end up with an employee that's just not meeting the basic expectations and making too many mistakes, and so hopefully the store manager and/or district manager are taking the appropriate steps to either help fix the problem, or get rid of it. I'm sorry you've had such a lousy experience with Leslie's, and I can understand your frustration, so I hope this helped a bit.