I have a client whom I suspect is just attempting to find ways to not pay invoices due, asking me to remove and change details continually on my invoices. Today they have requested that I remove the tax column on my invoice that states on the line no tax charged and also the subtotal line that states subtotal no tax because I am not VAT registered.

The invoice clearly reads that no VAT has been charged and no tax has been applied. I'm sure that this is correct although I could be wrong? Should I just remove this entirely for any legal/tax reasons or is the client potentially just using this as avoidance to pay?