Zeerust Pick n Pay, He picks and doesnt pay!

I run a local community newspaper, which relies solely on advertisers to be able to publish and run the paper as it is free for the community. I have on 2 occassions worked with Niel at Pick n Pay family store Zeerust and on both occassions there have been issues, but the second one has just made me realise I cannot keep quiet. Niel is VERY aware of the papers circumstances and I gave Niel heavily reduced tarriffs as I was pleased he chose to advertise with us. First time, after it is clearly stipulated on the email, that once the advert is approved payment must be made, he made me ask for payment and then told me I would be paid like all his other suppliers (I am not a supplier) only at the end of the month. This time, after my deadline was stipulated, not only did he change the design and instructions AND APPROVE, he requested a final change once my paper was already in for submission for printing. When I explained to him that he did approve the design, he said NO WAY was i to proceed and then made an arrogant snarky comment about him being the customer and who was I to question him. Difference Niel is that YOU would NOT let your customer leave without paying, and YOUR customer would not delay and affect your production line and NEGATIVELY influence the rest of your loyal, PAYING customers. This has had a very negative effect on the paper and I have had to lose my spot in the printing queue and dissapoint my clients as well as my local community. Niel used to be a very approachable business man, I am afraid to say however, this is no longer the case. I habe taken a financial knock of R3400 rand, and as I explained, with this being a small, FREE, local newspaper, it is a knock I could ill afford.