Supposing that the part "semblent avoir perdu leur emprise sur moi" is correct, then what is missing is a subject for "semblent avoir perdu"; since this is the third person plural form, this subject has to be either a plural noun or a plural third person subject pronoun (ils, elles).
- Ils/elles semblent avoir perdu leur emprise sur moi.
Neither "Tes" nor "t'es" is possible.
Ajustment of the answer after the change made in the question by user Hansen
As I said avove there has to be a plural pronoun or noun, which should rather be called "noun group" ("noun" is to too precise in this context). With the phrase "s'il te plait" occurring between "Tes" and the verb, all becomes clear; "Tes" is now justified. "S'il te plait" is being nominalized, treated as a noun, so to speak, and it refers to instances of using the phrase by the person spoken to in their addressing the person who is speaking. It is as in English when you'd say for instance "Your good mornings are not what they used to be, you are not as kind.". So, the person talking is saying that his/her use of "s'il te plait"'s are not as successful as they used to be in the way of getting something from him/her, in the way of pleasing him/her.