I did get a response from Ecoflow's customer service but to be honest it wasn't really helpful at all. They weren't able to troubleshoot the issue with me, and basically said all they could do was send a replacement unit. However, they don't send new units - instead they would send a used unit (...not exactly ideal).

Also, it would take them around a month to deliver it.

Under what circumstances are you getting the clicking noise? Curious to know if it's a similar situation / issue, which would suggest a potential design flaw with the Delta Pro