Cant display 8 on my digit display when given the time interval!!

Other Hardware Displays
4

As I said, theres nothing wrong with the segments and port connections that have to turn on to display a digit..
And thanks for the tip on the case part.. I was taught C++ in high school.. Never used "case 0: " or "case -1: " before...
When everything except the void loop remains unchanged and I replace the loop() with the following code:

void loop()
{
Dis(8);
delay(1000);
}

[note: I havnt given the command to reset all ports.. (the code line: off(0);off(1);off(2);....off(9);)]
I get a brief flash of 8 and then a blank display.. could there be a problem with the digit display? I bought 5 such displays of the same manufacturer.. All show this same output.. A BLANK SCREEN!!!

Again just to be clear:
For the loop() function to display just 8 WITHOUT THE DELAY:

void loop()
{
 Dis(8);
}

I get a good clear output of 8..