Incorrect Federal Refund for 2024 - After Submitting to IRS, Refund was double what TurboTax calculated

As the title states, I received a letter from the IRS regarding my federal refund, submitted the requested documents, and then received a refund nearly double the amount that TurboTax calculated.

 

I paid for TurboTax Deluxe Online and would like a refund or to dispute their guarantee that I would receive my maximum refund using their service, as I believe an error occurred in their calculations. How can I contact them? Y'all have made it nigh impossible to talk to a single human being considering I've used it for many years. Will not be returning next year due to the fact that y'all have likely low-balled my return for all these years and I do not trust these services anymore.