new water pump BUT no cold water!!

I installed a new water filter about 10 days ago. Usually, up until now they say, you could put the new cartridge in up or down and it would filter correctly. But they're now making filters, so I learned today, that one end is 'inlet' and the other end is blocked to make sure the water is filtered before it goes out into the lines. Consequently, I had blocked the outlet and therefore got zero cold water. Talk about mea culpa!! Thanks much for your imputs! Jim