Yeah, there was a problem with my OP6 USB port (charging was VERY intermittent, at-best), and I did a return, mostly because the "exchange" option was going to take 7-10 days, and I'd already "trickled down" my previous phone.
Not wanting to move back into the Win10 ecosystem at this point (the remaining phone around), for just a couple of weeks, I went ahead and did the return, and re-ordered (seems like most places have an "active swap" these days, where they charge your card, if you fail to return the old unit, once the new one is received, I fail to understand why OP doesn't have this...).
Anyway, I can't really say my return was "smooth", and in fact they lost track of my return, at their location, for almost 2 weeks (plus the shipping time, so almost 3, by the time they "found" it), and their CS basically had no idea, or really any reassurances, even though THEY HAD SIGNED FOR IT (or their US Acer-based return setup), so that was super-frustrating, and involved several long calls to CS.
By that point, I was VERY glad I hadn't done an exchange, as it would've been about 3.5-4 weeks, total, which is bordering on ridiculous, for a time-sensitive thing like a cell-phone, IMHO.
I'm sure you can find a lot of stories like this, about any cell company/OEM, if you dig around, but there do seem to be a large preponderance around OP, almost like it's "the norm".
I'm not sure I'll stick with them, moving forward, they still haven't fixed an auto-rotate bug, even though they said it was "in the branch" a few months back now, and I did get them full kernel traces, an exact repro, the whole bit. Their CS model is "odd", probably the best way I'd put it.
They have fixed several others, although one I had to actually "prompt" them, a couple of times, and show them where in the traces it was failing, to get them "back on track", for one network bug, that a LOT of people were seeing, that was "strange" to me too, coming from an engineering background.
If you're going to have a "super terrific" return policy posted, "no questions" and the whole bit, that's great and all, but, they should MAKE IT WORK, at least reasonably smoothly, if you ask me, or get rid of it.