Hello,
I am new here. P
Hi Johnny-
First you should consider contacting Aillio Support. I know it’s not a warranty issue but they are very good at guiding trouble shooting the problems from the drop.
With patience and some experienced guidance an owner with appropriate hand tools and reasonable skills can probably effect a repair. Just guessing but the knocking may be a bent drum shaft or drum belt alignment issue or even an issue with the pulley on the rear shaft of the drum. Clearance between the drum and the surrounding insulation and the induction coil is pretty close. And there are several videos on the Aillio site under the Support tab that may help.
Also, if you bought from Sweet Maria’s you could contact them. Their Bullet tech (Julio) has helped me a couple times and is on PST instead of GMT+8 in Taiwan.
I appreciate you posting this. I’ve thought a couple times about adding a lip to my work bench to (possibly!) prevent what just happened to you. I think you may have given me the incentive to actually do it!
Bruce
Hi Johnny-
Well that ought to do it! 
Sweet Maria’s has some Bullet-related videos as well. May take a little digging to find but they’re probably on their ‘library’ server (used to be their ‘legacy’ server). Click on Videos in the top ribbon then search/drill down. There was more than one Article about the Bullet as well.
Bruce