WTF? You received no manual at all?????
I would have sent back that box immediately. Without a manual you will not be able to keep in in the long run, you will eventually fry the controller or the spindle or both, so the first thing I'd do is DEMAND the seller to give me a manual. If he can't provide that within reasonable time (1-2 weeks) I'd claim my money back. 100% of the costs + shipping and whatever else is paid (import duties or other charges).
Experimenting without manual will only result in failure unless you are lucky, so in my opinion, no point continuing without a manual. Perhaps it is already fried, but now that you have even admitted the seller that you have changed things and the box is no longer working, he will say that YOU fried it, it is your fault and that the warranty is no longer valid. So, in my opinion you should contact the seller once again, give him one week to send you a solution proposal for the right settings AND the manual so that in the future you can fix it on your own. If he is not delivering you must claim your money back including shipping costs back to him, BEFORE shipping it back to him. Otherwise you will never see your money or the box again, no matter how well organized the Australian consumer protection is.
BTW, I agree with Mactec54, your parameters seems to be totally wrong, it looks like it is set up for 50Hz motor, but in my opinion, they look wrong even for that. Note that you cant just change every "50" to "400", that would probably not be a good idea unless you really know that you have to do it. There are other parameters also, like maximum current, RPM, power and so on. So, without a manual or another person having an identical box, I don't think you have a big chance of fixing this, especially since you don't seem to remember what you have changed and from which value.
Look what I found by searching eBay:
USB Port CNC Router 6040T Graviermaschine Fräsmaschine 1500W Spindlemotor VFD | eBay
Here is another one:
4Axis CNC Router 3040T Graviermaschine Fräsmaschine 800W Spindlemotor VFD Engrav | eBay
Is this your machine? Contact the seller and ask if you can get a manual.