As well as having an amazingly wide range of stock, I've just discovered that Cult Pens also provide excellent customer service.
A couple of months ago I bought a OHTO Super Promecha mechanical pencil from them - it also happened to be the cheapest price I could find. As usual, it arrived next day. Nice pencil, it went into my pencil case along with ten or so others.
Then last week as I was using it, the lead ran out, and the expected new one wouldn't feed through. I thought maybe that I had used leads that were the wrong size, but no - no 0.7mm leads would feed through. After dismantling the thing, I discovered a tiny bit of plastic caught in the jaws of the clutch. I'd no idea where this came from, but it was obviously part of the pencil. I thought that I had better ask for advice.
Their response was quick, with instructions on how to re-insert the little guide, which they admitted should never have come loose. This went surprisingly well, and the pencil worked. During discussions with Cult Pens, they did say if there was an ongoing problem to let them know, and they would replace it.
The next day I thought it might be a good idea just to check what happened when the lead ran out. Guess what? the new one wouldn't come through. When I emailed Cult pens to let them know (at 4.30pm), the almost instant reply was that they had just shipped that day's orders, but would send me one the next day.
True to their word, I now have a new pencil, that works.
No affiliation, obviously, just a very happy customer. Thank you Cult Pens. Now, I think I need to try their own brand inks ....