Hello Sharad,
What you may consider noting somewhere or communicating to everyone is that the phone is QC 3.0 compatible, but not PD 3.0 compatible. Functionally what you are saying is the same overall, but expressing which protocols are actually supported is likely a better method – noting that QC 3.0 chargers are USB-A to USB-C type chargers. As such, the phone should be advertised as compatible with QC 3.0 standard but not the PD 3.0 standard.
What is really confusing about this is the way that people are seeing things packaged / marketed, QC 3.0 was actually the original protocol used for USB-C charging, so it is very likely that Chinese documentation on the chipset advertises it as USB-C charging compatible, however, doesn’t outline that the protocol of compatibility for USB-C charging is only for the QC 3.0 standard, thus not supporting USB-C to USB-C charging or PD 3.0, but still a method of USB-C charging as your original advertising / marketing would suggest. Likely not your direct fault, but I can see how some will still see this as disingenuous.
Possibly adding something about the terminology and clarifying what was really meant in your advertising in your next update on Indiegogo could help to correct peoples expectations and lessen the backlash / outrage.
Just to be clear for others reading, even though it supports QC 3.0, this still doesn’t mean it supports fast charging, just that the charger will be compatible with the phone and charge it.
My 2 cents.
Cheers!