Local files replacing original tracks

[Spg13]

There are a few songs that I have downloaded on my phone as local files because they were not on spotify at the time. These songs are now on spotify but some are slightly different and I just want to listen to the spotify version. I deleted all of my music from my phone and downloaded it hoping that it would change, everything ran smoothly until I got onto my computer, it then downloaded all of the old local files onto spotify and replaced the spotify versions.
Sorry if i didn't make sense, I've taken a solid half an hour trying to get these words