Initiating a large interior home reno. Dealing with one main retail business that supplies flooring, kitchen and bathroom supplies plus will install and complete plumbing and electrical. Was planning on putting through my credit card to achieve travel points. They however have frowned on this process and request cheques as the credit card company charges them a percentage to process and they loose. I can see possibly not processing through credit card on labour, but actual products like sinks etc. Can they specify how I pay? Reno will be over 100,000.00.
Thanks!

Yes they can refuse to do business with you, if you don't pay the way they want.

Yes, but you also can tell them that you will not do business with them, unless they let you pay the way you want. I doubt that the losing of a few percent will let you walk out the door.