HAKII Action is a pair of in-ear earbuds, which means besides hanging them behind the ears with the ear hooks, users should also make sure they have been properly inserted into the ear canal to fully utilize the earbuds. So please try to adjust the way of wearing, and properly insert the earbuds into the ear canals for better sound quality. We saw improvement on the sound quality from similar cases with these methods.
Also, please try using different size of the eartips and see if it can solve your problem. By using proper size of eartips, the acoustic environment in the ear canal will be improved, and thus a better sound quality.