Capital Float — Not responding for my complaint

I have used amazon pay later option powered by capital float. after that i paid all the amount to capital float but bank charge me ecs/ach charge from my account. I contact the branch manager about the problem then he said we don't have any authority to cancel this charge .please contact your loan lander for the same. I contacted capital float and amazon about the problem but they didn't respond. I have lost nearly 3000 ecs charge from my account