Changing Tempo for Beatmatching without Changing Pitch

I am using the most up to date Serato DJ with a Numark Mixtrack Platinum as the controller. I want to easily change BPMs and the songs tempo without changing pitch. The only way I've found to change BPMs is to manually tap it in or write it into the the song library grid. But this does nothing to change the actual speed of the song, so it seems a bit pointless and I am unable to beat match two songs except by ear. I contacted Serato about it and they say the only way to change a songs tempo is by using the pitch wheels on my controller. I don't want to shift the pitch of songs to match them up, and even when I match the BPMs of two tracks using the pitch wheels, they are not actually playing at the same speed. What exactly am I doing wrong and how can I shift the tempo without changing the pitch? I have used Serato before and have always had an easy time adjusting songs' tempos to beat match without shifting pitch.

On the very left and right of the controller (next to the jog wheels, at the end of the controller) you can use the pitch faders to speed up and slow down a track.

To lock the pitch, make sure keylock is on. It is a little music note button next to the jog display on Serato DJ. Here's a photo of it:

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