Hi Jose, I feel for you, I really do, I've been there, and I've wiped out many seeds using the paper towel method on a heat mat, but this is how I know its a terrible way to attempt germination from experience, once I learned a little more I was much better able to understand why it was not the best method to use. One of the most important things to keep in mind when trying to germinate is consistency in the environment, it's vital that the seed has enough time in prime "spring-like" conditions to germinate. Using the paper towel method it's easy to oversaturate in water causing a blockage of essential oxygen getting to the seed. Also, the heat generated from the mat will continually dry the paper towel requiring constant monitor and reapplication of water to keep paper towel damp but not soaked, this can easily dry out rapidly, and it becomes time-consuming to maintain moisture, oxygen, and temperature over a multi-day period, even a slight "dry-out" fluctuation in the environment during the critical stage of germination and its death, or the shell re-hardens due to drought, suffocation lack of oxygen.
I'm sure Herbies have their problems like all seed banks once in a while, most seedbanks have their own little recommended method for germination when you buy seeds, did they recommend paper towels? If so then I'd steer clear of Herbies myself, if not I wouldn't blame Herbies, I'd look to improve my own knowledge and understanding of the germination process and the optimal environmental factors which would greatly increase my germination success % if held consistently over a period of a couple days.
good luck.