Can anyone tell me why I received only a third of my return on Feb 27th and still have not received the reminder, nor received any type of letter or explanation?

Federal or State?  Federal and state refunds come separately from different places.

I don't know because the amount is different from the amount I should receive from state or federal. Online banking shows it is from AC-TCS TREAS?

That is Federal. The IRS will be sending you a letter in about 2 weeks.  They do not notify TT of any offset or adjustments, but you can check here:

https://www.irs.gov/taxtopics/tc203