Sorry that your connection came loose. I have to ask, did you connect and disconnect the MMCX connector repeatedly, or did you spin the housing on the connection repeatedly? Did the way you wear you DK-3001 put strain on the connection? Any/all of the above will compromise any MMCX connector. It's one of the weaknesses of an MMCX connected earphone. Good news is that a new cable will make this connection good as new.

Try to get in touch with Dunu, they should be able to help you fix the issue, especially as you should still be within warranty.