I delivered a service 6months ago.
My last invoice included interest at 2% per month.
My quote did not indicate that interest would be charged if not paid within a certain period of the original invoice.

Payment of the interest was refused because it was not indicated on the quote.
Am I legally entitled to the interest charges?

In order to avoid repetition I intend including a clause to my quotes stating that interest charges will be applicable if not settled within 14days of service or invoice(still to decide). What is the maximum % I can ask? My goal is to deter late/non payment.

Thank you
Sparks