Rediculous supplier procees of Wesbank

My Business is in Marloth park and need to buy a generator. There are only two suppliers in Nelspruit, Both supplies exactly the same product, but the one is R20 000 more expensive. So the problem is that WESBANK approved my finance but they will not pay the lower cost supplier because they are not on their "Supplier approved list". This is absolutely ridiculous. Its not up up to wesbank to run my corporate governance, it is my company and I select my suppliers not you. You only finance the products, there's no risk to wesbank. The higher cost supplier has a delivery of five weeks, where as the lower cost have in stock. The "Approved" Supplier dont do their own installations, I have to get someone else, just a reason void warrentees.

HOw does you brains work