Recorded at 48000 but saved in .wav in 44100

The difference between 48k and 44.1 isn't anything like that great - in terms of pitch it's about a semitone. So if you've got 55 minutes that comes out at 17, which is about 3 1/4 times as then whatever it was that caused this, it wasn't that, or those weren't the numbers!

The basic process to correct this is to use Edit>Interpret Sample Rate, and then use Edit>Convert Sample Type to resave the result.

Having looked at your sample (which will never play properly because it's an MP3 and you can't really stretch those at all) it appears to play for 55 minutes if you interpret the sample rate as 16k, which is one of the drop-down options. If you have an original file that isn't an MP3, but is a wav file, then this should sound more or less correct. At that point, you just convert that result to 44.1k, resave it, and that will be as good as it gets. Depending upon what you did, the quality may still not be that great, but that will be as a result of any low sample rate and the Nyquist frequency limitations - the highest frequency you'll have on your recording is half the sample rate. But it will still sound better than trying to stretch it.