Having purchased from AC4L many times, the only occasion requiring me to contact them about any issues was when I bought a reconditioned Onkyo PR
-SC885 processor from them some years ago, back when they were on closeout. I had passed on the ShopOnkyo website sale and after changing my mind some time later, ended up paying a little more from AC4L...but it was still worth it. Being reconditioned, the unit did come with some minor internal issues however, but I sorted them out myself after contacting AC4L.
Back then, they offered free shipping back to them and another unit shipped out to me in exchange. I passed on the exchange when they said it was all right for me to open the unit and try and sort out the issues, which I did successfully (pinched wiring for the front display panel (easily relieved) which was causing display loss when pressure was applied to the front top left corner and some larger replacement screws needed for the AC connector, which had actually pushed into the unit when I tried to connect the power cord). Perhaps most would have returned the unit but I was concerned that the supply might run out or that I might get one in worse condition. Either way AC4L stood behind what they sold to me and handled the situation to my complete satisfaction. The unit still remains one of the best investments I've ever made in audio.
So I guess the lesson learned when buying anything refurbed/reconditioned is to always expect an issue or two and consider yourself fortunate if there are none. If the company has a solid reputation they will usually make things right.