Why you should never buy to Gearbest

Wow, Gearbest is showing their incompetence in many ways lately! I just learned that the DQG Hobi, for which there is an on-going group buy currently, just went on sale for a lower price than the group buy coupon code gives! And, if you apply the coupon, it reverts back to the higher price! In other words, the coupon can’t be stacked on top of the sale price discount. What were they thinking? If they were that desperate to get rid of the Hobi’s why didn’t they give us a better price in the group buy?