I went at Westmarine again and this time I didn’t take no for an answer. They’re going to refund me. I think at this point for $70 I can get a whole new MPPT with bluetooth and don’t need the $41 dongle. For all I know I could have gotten a brand new dongle and the problem would be with the MPPT (it’s old) and then I’d need to buy a new one anyway. This works out much better.
Thanks for your help!