How to escalate a non resolved support case

Hi,

We are going through a bad experience with Dell Support : We have had, on July 30th, an incident on storage device. a piece replacement is needed. our contract support mention that the piece should be shipped within the next business day. But until now it wasn't, we kept sending them reminders for the last past 2 months, they just ignore our emails. we tried to engage our account manager, but still no result. We called the support last week, they said that they will get back to us by emails, but they didn't.

Everyday past, the risk become bigger for our data safety and systems performance. Can anyone advice how we can escalate this to a higher level that can bring a solution for our case.

Best Regards