In general, confining / holding anybody against will is a crime and the confiner can be sued. However, the information given by you is incomplete, sketchy and apparently distorted. Please note that:
Hospitals don't go about confining patients against their will. [If they have, you can complain to the police; Medical Council; and, Consumer court in case it was not a totally free hospital for all.]
No hospital has to lie to a patient. If they have given a statement to the police that you tried to kill yourself, it is not a lie made to you. If the hospital has given you a document [Discharge slip, OPD card, etc,] that carries wrong diagnosis or statement, you can again complain to the Medical Council; and, Consumer court.
If the police has registered a case against you for attempted suicide, you have to defend yourself in the case, producing evidence against the hospital for producing false or wrong documents.