Great Tool ,Bad Back Office Account Support

Great tool for Accounting and SME Invoicing & Bookkeeping! just disappointed with ability to follow up and allocate monthly payments by their back office. If you paid and didn't wait for receipt to come through and log off too early, your payment is not recognised. Or if you over pay subscription that account doesn't seem to carry over to next month! Now they owe me 3 months subscription and each followed through with their call centre with no resolution for close to 8 months now for the first 2 payments and even the last thought i was promised it will carry through seems not.