Listbox not showing all the data needed

Welcome to the Forum KH97!

The issue seems to be "duplicates with slightly different information". If they have slightly different information, they are not duplicates. Your code looks for a case-insensitive exact match. What do you want instead?

By the way, the If statement logic is redundant. The current line of code is

If H = 1 And LCase(Sheet1.Cells(i, J)) = LCase(Me.TextBox1) Or H = 1 And Sheet1.Cells(i, J) = Val(Me.TextBox1) Then

but you can get identical results with

If H = 1 And LCase(Sheet1.Cells(i, J)) = LCase(Me.TextBox1) Then

Also, it would enhance the readability of the code if it were indented to show structure.