Thank you very much for your responses and suggestions.
I am glad I used a credit card instead of my debit card. I have contacted the credit card customer service and they are sending forms appropriate for disputing the charge.
Since I now have the OK from my cardiologist, I shall gather the components (already have all tools) and build the wheels myself.
I have become very apprehensive about ordering from a company that charges a "restocking/cancellation" fee. I am suspicious that the scam is to take an order (possibly no intention of filling it), perpetrate cancellation by putting the customer off untill cancellation, and collect the "restock/cacellation" fee with no expediture/effort.
TRUST has become obsolete for me.......Please be cautious!