IRS CP60 Notice but they have payment from me on my account from well before the notice was generated? Should I pay again?

I had issues with my payment for this years taxes going through, that made the payment fail at the last minute so I had to pay again and the new payment only went through the day after the tax deadline.

(I started the payment two weeks before the deadline and idk it was messed up from the start somehow I guess because it says its a returned payment in my IRS account, except it never even went through in the first place)

So obviously that sucks, but I received a letter in the mail about payments incorrectly applied to my account being removed and now it says I owe the interest and penalty which is like a $1 and some change more than what my second payment was.

The money I gave the IRS for the initial payment, are they going to give it back? they have not yet, and I've tried to call them everyday since last Friday at the number on the notice, which was a 0922 number and then the number on the website and every time it goes to put me on hold I get kicked off the call because it says high call volumes mean I cant even wait on hold. I've called at 7 am everyday, and even on Wednesdays and Thursdays when volumes are supposedly less.

I don't think it will be possible for me to get ahold of anyone before the deadline for increased penalties, should I just pay again? If I pay again will they give me back the other payment I gave them? I see a payment returned but it was the original payment that wasn't working and nothing ever came out of the acct in the first place and the date isn't even the same as the one on the letter. I paid the other amount well before the date the letter says it was generated, so why didn't they see it when they made the letter? Should I just pay the full amount again or only the interest since that's what they technically don't have from me? Or is the other payment just floating around in limbo and they will keep it but never use it for my account?

My IRS account says I don't even have a balance and it never reflected a balance from the start I just knew I needed to pay from filing. Since they've clearly looked at it already shouldn't the balance have updated by now?