到客户抱怨产品质量的信，该怎么回复？

昨天发了一封邮件给很久没的老客户。今天到他的抱怨信，说以前从我们公司的产品质量不好。我该怎么回复呢？这些产品的订单是之前的同事成的，我刚来公司不久。以下是客人的抱怨的内容 thanks for your email. we had bad experience dealing with your products. the led light we bought from you- all of them had to be recalled in six months because all of our clients complained- battery getting defective, led blow out, clip fixture frequently getting loose etc. the hand pieces that i got from you- all of them had to be discarded after three months of use ! i think quality??and product testing is someting that should be done prior to selling products to distributors.