There is no set time for an ARC to be processed. Some can take as little as a few days, while others can take months - upwards of a year.
It depends on the numbers being processed at a particular visa post, how complex the case is, obtaining a response from CBSA where asked about removal fee repayment costs or any concerns they may have about return of the individual and follow-up on those concerns and finally a decision to issue or not.
So patience will be needed along with the understanding that there is no guarantee it will be granted or that it must be.
