1. First obtain anticipatory bail in all the cases where FIR has been registered, then challenge the cases on merits one by one.
2. Court will not take any action on its own. You have to file a petition seeking direction of high court to the concerned police to not to harass yo on some false and flimsy cases without proper enquiry into the complaints made before it.
If you have grievance agaisnt the police then you may file a private complaint agaisnt the police u/s 200 cr.p.c for proper action under section 182 IPC.
3. Without facing trial you cannot seek to invoke any such provision, you have to prove it in trial proceedings the observations or irregularities.
4. You cannot ask court do such things without filing a petition and an affidavit on the said grounds.
5. Writ cannot be filed against state in the prosecution of a complaint lodged by a private person.
6. Civil case is not maintainable.
Why dont you lodge a counter complaint against this person for the same offences, namely extortion, black mail, threats to life, harassment, nuisance etc.
7. Even before the investigation report and charge sheet is filed, you cannot seek re-investigation.