This assumes that the job descriptions are in column C. Two lines need to be adjusted to meet your situation.
Dim customerName As String
Dim customerSheet As Worksheet
Dim descriptionString As String
On Error Resume Next
Set customerSheet = ThisWorkbook.Sheets(customerName)
On Error Goto 0
If customerSheet Is Nothing Then
MsgBox "No such customer"
Else
With customerSheet
If IsError(Match(descriptionString, .Range("c:c"), 0)) Then
MsgBox "Customer " & customerName & " does not have " & descriptionString
Else
MsgBox customerName & "'s " & descriptionString & " is in row " & Match(descriptionString, .Range("c:c"), 0)
End If
End With
End If