if they are feeding and actually eat, i think that is a good sign. acans are very hardy. i accidentally had a frag which i broke in half (hit it hard on accident with magfloat) and now its 2 acan frags.
although they do look freshly cut, im not sure. my expereince with fresh cut micros (not acans) wasnt good, and all the flesh came off the skeleton. so it might just be stressed from shipping (not because it was fresh cut)
lastly, a business is a business. and they can be very busy. like u said, im sure they are just busy, and will get back to you at some point.
anyway good luck!