Irresponsible

How can some be so irresponsible about the things they do. Despite grace given for a week, I have yet to receive what should be done a week ago. I honestly think it's a buyer's responsibility to pay on time + meet on time, same goes to all sellers. Honestly think I'm selling my products at a VERY low price. I don't even ask for payment or deposits first because I'd rather receive payment on the spot so my customers gets the product immediately after paying. I did give a option of transfer or payment on the spot. If you agree on paying cash ON THE SPOT, please keep to what you say. I do trust my buyers, however I think I should come up with a strict policy of receiving payment first since some can't stick to their responsibilities. I want to trust, but seriously? Just very much disappointment received, i'm doing a business not charity work here. I hope everyone understands where I'm coming from.