A, D, E, F, G, DP are lit instead.
Rather than sending a number, send the opposite of that number.
For example, instead of
shiftOut(datapin, clockpin, LSBFIRST, segdisp[z]); // sends the digit down the serial path
Use
shiftOut(datapin, clockpin, LSBFIRST, ~segdisp[z]); // sends the digit down the serial path