TPG Products only returned a small portion of my federal refund

Do you know for sure the IRS  sent out your full refund?  Maybe the IRS adjusted it.   $1,400 is the amount of the 3rd Stimulus payment. Did you already get the Stimulus payment they sent out last year starting March 2021? Do you have 1,400 on 1040 line 30? You might have tried to claim it again. Line 30 is only if you didn't get the full amount or qualify for more.

Did you get IRS letter 6475 saying what they sent you? If you didn't get the IRS letter 6475 saying what they sent you then check your bank statements and check your IRS account to see when and what they sent you.
https://www.irs.gov/payments/your-online-account

If you didn't get the 3rd Stimulus check but the IRS shows they sent it to you then request a trace for a missing third Stimulus payment
https://www.irs.gov/newsroom/questions-and-answers-about-the-third-economic-impact-payment-topic-j-payment-issued-but-lost-stolen-destroyed-or-not-received

It is possible that the IRS reduced your refund.  The amount of about $1400 sounds like you might have had a mistake with the recovery rebate credit.   If so, you will be receiving a letter from the IRS.

TurboTax does not get any information from the IRS after you file your tax return, so no one at TT knows why your refund was less.

 Sometimes we can make an educated guess as to the reason for your reduced refund if you mention specific amounts--for example if your refund was short by $1400 per person---it is likely to be a mix up regarding the 3rd EIP payment.    If you received the 3rd stimulus check of $1400 per person in 2021 then you got letter 6475 from the IRS about it.   You needed to enter the amount you received.   If you already received that money then line 30 on your Form 1040 should have been blank.

  If it is short by $1800 or  $1500 or  a multiple of that amount  ---   maybe a mixup regarding the advance child tax credit payments. If you received monthly child tax credit payments of $250 or $300 per month between July and December of 2021, then you got letter 6419 from the IRS, and you were required to enter the amount of the advance payments.   Only the remaining amount of the CTC should have been on line 28 of your Form 1040.

The IRS knows how much they sent to you for the 3rd stimulus check and they know how much they sent for advance child tax credit payments.   If you answered something incorrectly on your tax return then the IRS made a correction that resulted in a reduced refund for you. 

 Or---the fees you were supposed to pay for using TurboTax + the "refund processing fee" charged by the third party bank….

Did you choose to have TT fees deducted from your Federal refund?  (Remember that if you did that, you also agreed to an extra refund processing fee of $39.99 or $44.99 in CA)

How can I see my TurboTax  fees?   

https://ttlc.intuit.com/questions/2565973-how-do-i-review-my-fees-in-turbotax-online

What is Refund Processing Service?

The IRS will send you a letter that explains why your refund was reduced or why you owe more.   Meanwhile it might help you to check your online IRS account.

https://www.irs.gov/payments/your-online-account

https://blog.turbotax.intuit.com/tax-refunds/why-is-my-tax-refund-not-what-i-expected-49240/

https://www.irs.gov/newsroom/questions-and-answers-about-the-third-round-economic-impact-payment-topic-j-payment-issued-but-lost-stolen-destroyed-or-not-received

If you need to trace a payment that the IRS says has been issued to you, mail or fax a completed IRS Form 3911, Taxpayer Statement Regarding Refund.