我理解在目前市场严峻的情形之下，您对我的产品的所有抱怨与指责，并保证有则改之。恳求翻译

I fully understand your complain about my product under current difficult situation, I ensure you, I will improve it and the same problem will never happen again

PS,不了解上下文背景，但一般来说，商务之间的往来，都是称呼我们(we)，而不应该是我(I)

I could understand you complaints about our products and relevant blames in the grim market nowadays. And I guarantee I solve our product's problems.