How does a trade in work

Looks like this is my platform for communication I recently posted here about my vehicle standing at the mechanic for a month after sharing I got assistance and received my vehicle but little did I know the next day the cars fan wasn't working the check oil and water light was on even after I filled both and when traveling on a steep the vehicle looses power I asked for a trade in rather because it was senseless to be spending money on a car that is standing in my yard or at the mechanics, they asked me to choose a car and then communication died.

Does anyone from Webuycars know how the process is supposed to work please can you assist me