Sentry Calming Diffuser for Cats, Diffuser

I have several rescues of varying ages, two veterans, and three new, one almost a year old. The Older cats did not like the invasion, the new rescues were afraid of everyone/thing (cats/people other than me) it was a precarious detente, much tension, marking, and when the kitten came all heck broke loose. I tried a few suggestions; the calming spray alone had no effect. I tried the feliway diffusers and they leaked and got hot and not only did they not help, the fastidious cat who 'warned away' the old guard got more vocal and started swiping at anything who approached, even swatted at her fellow familiar rescue with whom he formerly got along. He pretty much stuck to himself, & wiped the walls, when I used that diffuser he even sprayed (first time) and got more anxious/vocal. The other sweet fraidy cat who just hid from everyone until she came for lovey kisses and cuddles & pets actually became aggressive toward the other cats (maybe a coincidence, just had enough?) but still afraid and stopped coming to us for love as much. FORTUNATELY I bought the Sentry diffuser and although there is still some in-fighting, things have calmed back down to the initial unrest. Also it was supposed to last a month; it lasts about 3 weeks. But at least it doesn't leak or stink or get hot and I think it's doing something... SO I can't give this 5 stars, but I think it helped some; definitely better than that other brand for us! I was disappointed I couldn't get the replacements for this Sentry currently at Chewy, hoping to give it another go & see if it really makes a difference; hopefully they'll bring it back, maybe in multi-packs? Chewy's so much affordable than (other famous pet places) & their service is fast riendly and professional. CHEWY.COM has been GREAT support, and cared when I told them about the other brand leaking (& a bit of burning scent). They really care & try to recommend the product you need and help you deal with problems. They're super fast on shipping & their prices are so reasonable. I just hope they get this item back, or the other (3rd brand I'm having to try since they don't have this) works.