T’ not accepted?

Adi, 

“ T’as “ is an example of an informal contraction. It is considered quite ‘ casual ‘ and its use is restricted normally to everyday, familiar speech or found in abbreviated writing such as informal text messages. 

It is not considered ’ correct ‘ French in standard writing or more formal speech. 

https://www.lawlessfrench.com/pronunciation/contractions/

 https://www.lawlessfrench.com/grammar/informal-pronouns/