Capital One/Walmart card Refused to credit disputed amount back to card salt lake city Utah

Was told, " We don't keep records like that". Asked them: " What time of day, or night were the purchases made?" Was told: " We don't know".
- You called Customer Service who does not have access to that information.

Your dispute went over to the fraud department which in general you will never talk to this department directly at just about any bank.  They have not only full access to time/date, but they can contact the store and narrow it down to the specific register and yes even track it back to the items that were purchased.

They sent a letter stating all charges would be returned to card
- What was the exact words?  As generally they will say something like they would do a temporary credit until the investigation is complete.  It would be rare to get a letter like that within a day.

The next day they sent a letter stating that myself or another account user " benefitted from the transactions".
I am the only account holder, and I sure don't like being called a " liar," by Capital One.
- You got basically a standard "denial" form letter. 

Were these transactions done at the same store you shop at? That information should be on your statement. Then depending on what the fraud department found they could figure that you either gave your card to someone or otherwise had knowelge of the charge. Some companies have even gone to viewing the security videos and seeing if the description of the person using the card matches the card holder.

The first thing they did was send me a new credit card. So, if the activity wasn't fraudulent, why did I get a new card?
- It doesn't matter if the dispute is valid or not. If you even suggest that your card was compromised just about every bank out there will issue you a new card. It costs them pennies to do this and it could save them money(and protect you) in the long run if in fact the card was compromised.

Don't expect much of an answer, but you may need to continue to fight this by contacting them and asking how they came to that justification?  I would also make sure you are following their dispute process to have it registered.  This may include a call and/or filling out a form and sending it to them via mail or through email.