Worst Service in the History of Mankind

Kelloggs is a one our suppliers, and they have a large range listed within our stores, I myself handle the Replenishment Planning within our company, however after 100s of emails and escelations, I am now forced to complain on this public forum. First of all, our order are NEVER delivered within the specified lead time. We follow up multiple times with absolutely no responses. Order cycles has been changed so many times to mitigate this issue, yet it solved nothing. Our Buyers have intervened, we have asked nicely, there has been meetings.... yet - the worst service experienced from any company in my entire life!!! Please Kellogg's, if your staff cannot do the job, get people who CAN!!!