Sandra,
[Original reply translated into English as nickel helpfully suggested.]
You are obviously translating a legal text (lawsuit?). Translating legal documents from or into English is arguably the most difficult kind of technical translation. The reason: The Anglo-american legal system is very different from continenal legal systems. Only a lawyer familar with both systems is capable of producing a proper translation. So it is not surprising that you encounter difficulties, especially since your Greek is not perfect. If you can, show your translation to a lawyer friend of yours and ask for his or her opinion. It is very likely that your translation will have problems.
Let me try to help:
διασχηματισμός= Never heard of this. Thanks to nickel for explaining!
αποκτήσει (υποτακτική [να αποκτήσει] ή μέλλοντας [θα αποκτήσει] του αποκτώ)= to acquire; to obtain; to get. What is the context?
αντίδικος= opposite party. However, it is an expression very rarely used in English. "Plaintiff" or "defendant" are preferable terms. On the other hand, if this is not a simple lawsuit that we are dealing with but a special procedure, other terms may be preferable.
επελέχθη (αόριστος του επιλέγομαι)= to select; to choose
The sentence you are trying to translate features all the typical qualities of Greek legal writing: Poor and opaque writing and long sentences to boot. Not a piece of cake to translate. It could be translated as follows:
"The opposite party (better: "the plaintiff" or "the defendant") claims entirely falsely that, following her testimony as above, she has acquired rights also to class 30 products, allegedly in good faith. "
My translation retains the flavour of the original text. (In this case, not a particularly good thing!)
Notes:
εν συνεχεία: I'm not sure what this refers to.
κατάθεση: May be translated as "testimony" or"deposition". Depends on whether the testimony took place inside a courtroom or not.
Hope this helps.