Turbo tax says I’m getting the biggest refund 5,000 but I got a letter in the mail from irs stating I’m only getting 2,000 due to miscalculation and nothing on the list shows anything that could have effected my return to give me such a lower amount

Turbo tax says I’m getting the biggest refund 5,000 it shows that on my profile and it shows that it was accepted by the irs two months later I get a email stating from turbo tax that I will get my refund in a couple of business days  but I got a letter in the mail from irs stating I’m only getting 2,000 due to miscalculation and there was a list showing things that could have caused the miscalculation  nothing on the list of what could have gone wrong matches my situation at all do I contact the irs ? I was told not to until my money was deposited into my bank so no more confusion would be made but I feel stuck..