This happened to me also. They are telling me now that I am not allowed to use my rewards because I have purchased too much. Guess I'm moving to Lenovo 
Every order I have placed with Dell Rewards, the order is INSTANTLY cancelled without giving me a reason. This happened 4 times in a row.  If I place an order paying with the same credit card, same billing and shipping address, it goes through.  The same order while redeeming dell rewards, it will not go through with an instant cancel.  Each time this happens, my reward points are NOT refunded. I would have to call in 3 times to get my points reinstated, each time this happens, it takes 20 days to get my points back.  I placed my 4th order today with Dell rewards, and same thing, instant cancellation.  Can someone explain to me why I am not able to spend my Dell rewards points as the order is instantly cancelled without reason. Order date: Apr 28, 2022| . TOS76> Order date: Apr 9, 2022| . TOS76> Order date: Mar 16, 2022| . TOS76> Order date: Mar 13, 2022| . TOS76>  Just last week, I placed an order WITHOUT REWARDS, with the same billing address, same shipping address, same credit card and it goes through without any issues and I have received the machine; however, if I even add a single reward point, my order would be instantly cancelled. Please advice and fix. I have not been able to purchase using my Dell Rewards since March 13th. 
Dell Rewards Purchase Instant Cancel with No Reason Given