Return DA310, refund wait 10-15 days

I purchased a Dell product DA310 on 3/6. I then was browsing on Amazon and they had the same Dell Product $42.00 cheaper. I  asked Dell for the difference.  hey refused. So when the DA310 was delivered to me I returned it to Dell the same day. 3/8/2023. I have a FedEx tracing slip (I sent to Dell) showing that it was received back to Dell on 3/10/2023. I asked where my refund is? They claimed that the DA310 was not returned to Dell yet . 0n 3/16/2023. Once I took a snap shot of the FedEx tracking slip they updated their file to item DA310 was returned to Dell. Now they think I have to wait 10-15 days for my money. I was a controller of a fortune 100 company for 25 years. I never heard of for one not price matching a Dell product sold cheaper on Amazon. I'll never feel safe shopping at Dell. The second practice is making me wait 10-15 days for my money especially considering the circumstances. And third lying to me that they traced the return with FedEx and it hasn't arrived at Dell yet. My checking account became overdrawn due to this. They charged me $15 fine so far.

I want my money returned now. It took you seconds to charge me on 3/6 and will take seconds to credit my account. I have spent thousands of dollars at Dell. This is no way to treat a good loyal customer.

Dennis G