Loss of brake pedal: This condition is usually a result of brake fluid leakage due to failure of a brake hose or a rusted metal brake line, a worn wheel cylinder or brake caliper, or a worn master cylinder. A simple once over of the system will reveal what's going on.
If you have questions about a specific purchase, it would be best to speak to an attorney who could inform you of your legal options. While there are laws that allow for a 3-day right to cancel certain purchases, these laws are very specific and do not apply in a majority of consumer purchases.
If you want to cancel a Best Offer, use the Best Offer Cancellation form. If you won an item and you no longer want to buy it, you need to contact the seller. A bid on eBay is considered a contract, and you're obligated to purchase the item. Read about changing your mind about an item.