Parcels not delivering to our customers

we are a leading eyeglass provider online, shifted from other couriers, started leopard service since 5 months ago, only first month was bit fine then the service and support down and worst day by day. Resulting return ration too high more than 100+ returns without approaching to the customers (we have recorded the proof) for which we got much loss, the reputation and slowing our fast growing business just because leopard worst service. Also no response from supports, AC.managers etc.etc. Can anyone please tell is there chance to improve or you guys approaching to closeup the service soon.?