Gathering and packing the sold items under a reputable factory's name

Q: In 1397 A.H., I had a Mercedes truck with which I used to transport cement from Al-Dammam to Riyadh. I used to buy cement bags from Al-Dammam for thirteen Riyals and sell them in Riyadh for seventeen Riyals. It happened on some days that people would sell cement outside the port of Al-Dammam. This cement is the waste which the trains and ships throw outside the port. (Part No. 13; Page No. 214) Some people pack this waste cement in the bags of a Japanese cement called 'Abu Marwahah' which is the finest kind of cement. I have bought three loads of cement for ten Riyals per bag and I sell them in Riyadh for seventeen Riyals like the good products. Three people from Riyadh bought three hundred and fifty bags from me, and when they asked about the quality of the cement, I replied that it is as you see it. A purchaser buys when he sees the good product. I do not know whether the cement is good or not and I do not know the place of those who bought it. I am confused, please, guide me so that I may free myself from any blame. When selling the cement, I knew that this was cheating but other drivers told me that they would sell it on my behalf and when customers came to buy the cement, I used to tell them that it is packed, but the drivers asked me not to speak and told me they would sell on my behalf. May Allah guard you and set right your deeds.

A: The seven Riyals which are more than the original price should be spent in charity such as: money given to the poor, the Afghani Mujahids (those fighting in the Cause of Allah), fixing the toilets in Masjids (Mosques) and so on. You should also repent and seek the forgiveness of Allah (Exalted be He). May Allah guide us all to sincere repentance. (Part No. 13; Page No. 215)  May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.