Charge sheet

You can apoproach the higher police officer with a complaint about the long pending charge sheet in this regard.

According to Section 167(2) of the CrPC, a chargesheet has to be filed within 60 days from the date of remand of the accused and the same can be extended to 90 days for certain offences, i.e., it must be filed within 60 days or 90 days, as the case may be.

Pl.mention had the accused taken anticipatory bail from the court if not then you can contact to senior officer DSP or SSP for delay and lingering the chargesheet by the io . 

Accused not arrested till now Investigation officer didn't take any action against them

Except in grave cases like murder, rape etc Arrest is not necessary in every such FIR cases . Police may arrest . If there is the possibility of continuing the offence by the accused then arrest is a must 

As regards Section 41 of the CrPC, the Supreme Court has significantly observed that even for a cognizable offence, an arrest of the accused is not mandatory and that an arrest in offences punishable with imprisonment below seven years or extending to seven years can only be made if the IO is satisfied that there is a .necessity for such an arrest.