@Mahmoud With all due respect, this is not a professional answer that will gain you new customers. At least apologize for the error and say that it will be fixed. If I bought it from the official website, I will at least get support. You can request support from them if you bought it from the official website.
@Mahmoud No, This not right, If you are reselling, you have to bear everything, you have to communicate and fix errors. Why would I buy a script for fifty euros and then find that it does not work, then I have thrown the fifty euros in the dirt.