So I bought a purifier 3H from Mijia roborock or some say minihelpers is the same one from qoo10. They delivered the 3H but not the extra antibacteria hepa filter since Oct 15. Has been 1.5 months, despite chasers keep saying, arriving this week, 2-3 days delivery and not delivered all the time. Anyone encountered this issue? Is it easy to get a partial refund for the filter from Qoo10, or will they step in? Or anyone knows the IMM physical store locations? Or any advise how to proceed?