Did they open up the boiler and send you pics, do they say what chemical they usePaul @ ProPresso did a great job, with a remarkably quick turnaround time. The machine was very heavily scaled inside, despite me thinking I had done an okay job of descaling it. It turns out that even with softened water, you need to do it much more frequently than you'd expect to.
... if I had a boroscope I'd like to see what's happening in mine, through 1cm anti-vac valve hole, I remove , when descaling.
You dropped it off, I guess, would be $$$ to send by post/dhl ....