[Riing fans controller broken]

I have a couple of packs of Riing quad fans and one of the controller has stopped working after working fines for several months (it doesn't show up in task manager properly).  Fans are spinning and it has the default rainbow colours, but it is not controllable.  I have swapped the two controllers I have it and it shows the issue is one of the controllers.  If the broken ones is first when they are daisy chained the seconds one will not work.

I have emailed European & UK technical support (support@thermaltake.de & support.uk@thermaltake.com) and filled in the webform over the last 6 weeks.  Is there anyone looking a the European tech support?  as I've not heard anything back at all which is disappointing.

Thanks for any help.