The legal problem concerning consequences of determining the unfairness of standardized contractual terms and further the ineffectiveness of the whole contract is becoming more and more important issue in the days of growing number of cases which are questioning the legal validity of the loans indexed to the CHF. The prejudicial question was sent to European Court of Justice on the basis of one such case and the future ruling is about to be given considering legal argumentation presented in the opinion of advocate general – case C-520/21. The subject of the article deals with direct legal consequences of the ineffectiveness of the whole contract which included unfair standardized clauses. The main effect is duty to restore the consumer to the legal and factual situation and return of the values obtained by the parties to the contract. It also analyzes the further effects such as responsibility for damages on standardized clause user’s side and hypothetical compensation for the use of the obtained value by the other party. Legal arguments in this matter are based mainly on the aforementioned opinion and doctrine developed in Polish and German civil law. They are focused on presenting the preferred direction of UE countries domestic legislation which is obliged to ensure the full effectiveness of the directive 93/13/EEC. As long as directive opens the general possibility to introduce user’s responsibility for damages it is to be determined what specific legal ground for such responsibility would be. On the other hand, the general rule of law which forbids earning profits from the illegal actions eliminates the possibility of introducing right to compensation for the use of the obtained value to the domestic system of law.