Synergy Protection - This company failed to pay invoices in full - still owe $514.15 Ontario North York

We are a certified women-owned business with WBE Canada. We enjoyed a pleasant and productive working relationship with this company. We helped them to win several major contracts, which resulted in more jobs and the creation of a new division in the company. After a lengthy delay, several overdue invoices were paid, except for the last $514.15. After we sent several emails to request payment, the company ceased communicating with us. We can write off the outstanding amount, but it is disappointing.