How realistic is it to terminate the contract with the Energy Region in court. ...?

From the situation you described, it will be quite easy to win this legal dispute, since you have indisputable evidence that the apartment has not belonged to you for a long time. Also, after winning the case, you can collect the costs of legal assistance.

You need to file a claim in court in accordance with the Code of Criminal Procedure of Ukraine.

In accordance with Article 175 of the Civil Code of Ukraine, in the statement of claim, the plaintiff sets out his claims regarding the subject of the dispute and their justification. The statement of claim is submitted to the court in writing and signed by the plaintiff. The statement of claim must contain:

1. name of the court of first instance to which the application is submitted;

2. full name (for legal entities) or first name (surname, first name and patronymic - for individuals) of the parties and other participants in the case, their location (for legal entities) or place of residence or stay (for individuals) , postal code, identification code of a legal entity in the Unified State Register of Enterprises and Organizations of Ukraine (for legal entities registered under the laws of Ukraine), as well as the registration number of the taxpayer's registration card (for individuals), if available, or passport number and series for individuals persons - citizens of Ukraine (if such information is known to the claimant), known numbers of means of communication, official e-mail address and e-mail address;

3. indication of the price of the claim, if the claim is subject to a monetary assessment; reasonable calculation of amounts charged or disputed;

4. content of claims: the method (methods) of protecting rights or interests provided for by law or contract, or another method (methods) of protecting rights and interests, which does not contradict the law and which the plaintiff asks the court to determine in the decision; if the lawsuit is filed against several defendants - the content of the claims against each of them;

5. a statement of the circumstances by which the plaintiff substantiates his claims; indication of evidence confirming the specified circumstances;

6. information on taking measures for pre-trial settlement of the dispute, if such were carried out, including if a mandatory pre-trial dispute settlement procedure is defined by law;

7. information on taking measures to secure evidence or a lawsuit before filing a claim statement, if such were carried out;

8. a list of documents and other evidence attached to the application; indication of evidence that cannot be submitted together with the claim (if any); an indication of whether the plaintiff or another person has original written or electronic evidence, copies of which are attached to the application;

9. preliminary (estimated) calculation of the amount of court costs incurred by the plaintiff and expected to be incurred in connection with the consideration of the case;

10. the plaintiff's confirmation that he has not filed another claim(s) against the same defendant(s) with the same subject and on the same grounds.