reading a csv file in vbscript

I am using the below function to read a text file which has below format. I need to lookup the id (column1) and return date (column2). I cannot understand what is wrong with my code. So my code runs perfectly till readline, but some how it is not looping. So basically it just checks the incoming consumerSSN with only the first SSN from the txt file. So if I pass getDOH(213396391), it retuns blank(""), instead of its corresponding date.

sraDOH.txt:
578171533,2015-01-01 00:00:00
213396391,2015-06-01 00:00:00
077966385,2015-01-01 00:00:00
216418521,2015-01-01 00:00:00


Function getDOH(consumerSSN)
    dim fso : Set fso = CreateObject("Scripting.FileSystemObject")
    dim doh, t, x
    For Each File In fso.GetFolder(fso.GetAbsolutePathName("..\Test Files\")).Files
        If File.Name = "sraDOH.txt" Then
            Set tsIn2 = fso.OpenTextFile(File, 1)
            Do While Not tsIn2.AtEndOfStream
                doh = tsIn2.ReadLine
                t = split(doh,",")
                If consumerSSN = t(0) Then
                    getDOH = t(1)
                Else 
                    getDOH = ""
                End If
            Loop
        End If
    Next
End Function