Start with the basic default patch as described in the manual.
Reinstall the latest firmware
Restart it a few times in a row (not too fast)
Change the keyboard/gate switch on the back of the unit a few times, then leave it set on keyboard
Make sure your AMP knob on the LFO destination section is set at the center detent
Make sure you are monitoring it through the headphone or audio out jack, and those volume knobs are up
If you are 100% convinced that the unit is faulty, contact Arturia through the support section (register the Minibrute too)
Or, email the retailer and explain your situation with shipping. They might have a better suggestion.