I bought Tesla 3 6/25/2019...Seller told me that fed. refund will be 3750$ But after i submit all information at TurboTax form I see refund 7,5k is that correct amount?

After you file

No. It is probably this new error.....

https://ttlc.intuit.com/community/tax-topics/help/form-8936-qualified-plug-in-electric-drive-motor-v...

After you file

See this TurboTax support FAQ for the calculation error on a Form 8936 - https://ttlc.intuit.com/community/tax-topics/help/form-8936-qualified-plug-in-electric-drive-motor-v...