Breeze leaks - how can I patch the leaks

I've been using a Breeze nasal pillows device for a couple of years, and generally like it just fine. However, it has a problem with air leaks. The pillows themselves fit fine and don't leak. But the assembly the pillows fit into is actually a 2 piece assembly, and it leaks around the seam. I've gone through I don't know how many of these things, and they all leak. They start out with no leaks, then begin leaking, and get progressively worse. I'd like to seal the seam - obviously with something non-toxic and washable, and hopefully long lasting. Any suggestions?

I'd consider a five-minute epoxy. Use a bit of sandpaper or a wire wheel and dremel to rough the area around the seam, then mix and apply the epoxy to the area then smooth it out with your finger or a piece of paper towel.

Upsides:
waterproof
strong
cleanable

Downsides:
You basically only get one try to apply it
might not permanently stick to the plastic

Not sure if acetone will seep in and melt the edges together, whatever the liquid they use to seal plastic.

another would be to take a bit or vinyl adhesive- the type you use to install sprinkler lines.

What I do is take a soldering iron and delicately melt it together.

works for moi.

Tape. That's the short answer.

when i got my breeze over a year ago, the first one had just what you are talking about, a weak seam, that i think that they knew about as i got a replacement no questions asked. try getting or buying the endpiece, which i think comes with the hose for maybe $25-30. maybe write the company and 'complain'
i am still using that first one, complete with compliance over seven hrs a night. i am not a calm sleeper. so they are good once you get them set. i am using a Sullivan chinstrap that i figured out the best angle to pull up on my chin and then duct taped it to the top of the breze so it would stay in place and slide forward. i have now used this rig for over six months and tho most of the elastic is gone, it fits just fine still.