A customer troubled me in multiple ways - he has almost created a template for identifying bad customers

1. He returned some of the delivered material. Probably didn't need it anymore or got it cheaper elsewhere. Returns are very costly for the sender. Normally you can't return unless there's some defect.
2. When counted, the actual quantity of material in the return was less than what was claimed by the customer. However, the credit note from me was supposed to be made for the claimed quantity and not the actual received.
3. He called me to tell me that after sending me the return, the balance material that he did keep turned out to be less in quantity than what I said I had sent [net of return]. Meaning he was going to issue me a debit note for the "shortfall". I of course knew that this was a lie, since I always send properly counted material to my customers.
4. When the debit note was received, its amount was higher than the worth of the claimed "shortfall".
5. When it came to getting payment cheques [after the agreed credit period had passed], the customer made me hang for another 15-20 days. Some day he would say that he wasn't at factory, while another day he would say that he forgot the cheques at his home, and so on. Creative excuses. Needed to make 20-25 calls.
6. The day he finally gave the cheques, he made by employee [who had gone to collect cheques] wait for a full 2 hours before giving him cheques.
7. The cheques that were received weren't current - one [smaller one] was dated 10 days hence while the other [larger one] 22 days. Awesome!
8. Icing on the cake - the cumulative amount of the cheques was [somewhat] less than what was supposed to be the final figure!

One should stay away from such black sheep.