HY VFD 2.2KW Problem, Please Help

I have purchased a Huanyang 2.2KW VFD, the first time that I have powered it, I went over the various parameters and I was able change the values accordingly. The following day all the parameter values displayed “NULL”. Once Null was displayed it went to the next parameter and I was unable to change Null into any value.
(The VFD is not connected to the spindle and Not being controlled remotely)
I do not believe this being the case of the parameters being locked (PD000 =1) because I am also unable to change PD000 Null value to a numeric value. (By pressing Prog; PD000 is displayed; press Set; NULL is displayed; try to press up/down arrows while Null is being display (no change); Next Parameter is displayed.
(Note: Null is displayed for a few seconds ~2-3 sec, then it changes to next parameter; the outcome is the same for all parameters).
I have tried to removed and reinstalled the two ribbon cable connectors, but it did not fix the problem.
Your help is much appreciated.

Can you change PD013 to 8? That should be the factory reset. If you can try it, won’t hurt.

Thanks Doug for the reply. Resetting to factory values would have been a great idea; the problem is that I cannot change any of the parameter values. All parameter values show NULL and I cannot get them to change to a numerical value.
I have ordered another unit, and I will switch the control board to determine if it is root cause.
I also have contacted HY Electrical Co. twice requesting advise, but they haven’t replied.
Thanks again.