Use a variable when connecting excel to access with vba

I have had great success connecting to a access file through vba! However I am at a point where the column that I and querying could change. I would like some help altering me code. Thank you!

Dim cnn As New ADODB.connection
    Dim rst As New ADODB.Recordset
    Dim companyid As String
    companyid = Application.Transpose(Range("myid").Value) & "P"
    
    cnn.Open "Provider=Microsoft.Jet.OLEDB.4.0;" & _
             "Data Source=" mydatasource"

'This part works fine
    rst.Open "SELECT [" & companyid & "],[UM] FROM tblLineItems WHERE Item ='" & ListBox1.Value & "' ;", _
             cnn, adOpenStatic

    rst.MoveFirst
    With Me
    .itemlbl.Text = ListBox1.Value
'This part doesn't
    .pricelbl.Text = Format(rst! ["'" &companyid & "'"], "$0.00")
    End With
'......

I have also tried

.pricelbl.Text = Format(rst!['companyid'], "$0.00")

but it didn't work either

See attached for the error message

Just so you know if I don't use a variable in

.pricelbl.Text = Format(rst![222193P], "$0.00")

It works fine.

So I really need to know how to put a variable in there!