As far as Parts and products you or any non-company can buy direct from any China Manufacturer because of their export laws (long Story)
. The Manufacturer will only sell products by large amounts the lowest being 4 Tanks per CTN (Carton) at about 20 to 25 USD per tank and shipping will be added as well some only sell by the trailer load.
But they will sell you anything they have including parts.
Oh ya preferred payment is by T/T (Telegraphic Transfer) e.g bank Transfer
If you do this be careful of import Tax from your own country [&:]