Under this scenario it is impossible to know who or what was at fault, but if you contact them direct I'm fairly certain they would get you sorted out. Top notch customer service.
Nowadays, I have more of a lab mentality when opening, jarring, and handling my baccy, regardless of blender. What I do is I spray my bathroom down with 70% iso. I then suit up in a sterile full body Tyvek suit with full face shield respirator before going into a bleach bath contamination room. Once my suit is dry I.... I'm kidding, I'm kidding... While it's impossible to have a sterile environment at home, I think it is good practice to wear gloves, never open your tins outdoors, and make sure you are not jarring them too moist. So far I have been spared by the fungal gods. But there is only so much you can do, and taking it too far can make it not so fun.