Kosher prey and plunder

I heard of a restaurant that, among other things, sold terifa, and young people would order hot dogs there, and some of them were sliced. Later, the owner of the restaurant stopped selling terifa and sold only kosher, although not with a Rasmit certificate, because he wanted to avoid the strict requirements of the Rabbinate, perhaps so that he could be active on Shabbat. I don't know if he prepared the dishes. Later, one of the young men who had repented came to him and asked for forgiveness. He may have even paid him. Did he have to pay him? Did he need his forgiveness? And in the case where the owner of the business is a religious person who is accustomed to saying at least once in his life, "Rani Solh Ve Mohl," as appears in the siddurs of all the texts before the "Kash" on the bed? Can this be trusted?