We were hosting a Website and a CMS at an external supplier. They told us that they host everything on Microsoft Azure. Yesterday I saw that my website was down and contacted them. Later that day they told me that our server had a "virtual harddrive" failure. And the Data newest data which was not backed up is lost. I know that Ubuntu 14.04 OS was running on that machine. I also know that every storage on Azure is 3 times redundant if not more. Besides the temporary storage. Now I assume that they either used the temp storage for any activity or the failure was not a hard drive failure. I googled for any incidents like that in the past, but couldn't find any. Also all my own Azure machines are running happily for ages.
What could happen that a virtual disk failure will result in losing all my data? This should not be an opinion based question, meaning "do you trust my supplier". I would like to know the possible reasons for a harddrive failure on a 3 times redundant storage. Also assuming that no admin accessed Azure and stopped and killed the machine manually.