Is it obligatory to return ill-gotten gains to their owners for supplications to be answered, and is it permissible to work for the person from whom something was stolen, without his knowledge, in order to repay the debt?

Repentance from theft and similar offenses requires seeking absolution from those whose rights have been violated, either by returning what was unjustly taken or by seeking their forgiveness. If the stolen item still exists, it must be returned. It is not sufficient to return an equivalent item or its value unless the owner agrees. If the item has perished, then an equivalent item must be returned if it is a fungible good; otherwise, its value must be returned.

Working for the wronged party without pay, with the intention of settling the debt, does not absolve one's responsibility because such work has no wage, as it is for the benefit of the worker themselves.

The advice is to seek forgiveness and pardon from the shop owner, even indirectly. For instance, you could send a message stating that someone stole items from him and is now seeking his forgiveness. If he forgives you, your conscience is cleared. If he does not forgive you, then wait until you are able to restore his right.

Regarding the acceptance of supplications: if a thief repents but is unable to restore the right, and the owner does not forgive him, yet the thief intends to return the right whenever possible, it is hoped that this will not prevent his supplications from being answered, as he has done what is within his capacity.