How to block, mark as spam, or unblock phone numbers on Archos devices

Archos Sense 55s Archos Sense 55s
Archos Diamond Gamma Archos Diamond Gamma
Archos Sense 50x Archos Sense 50x
Archos 50 Graphite Archos 50 Graphite
Archos 55 Graphite Archos 55 Graphite