Clarification required. What is the time frame for seller mandated to accept a return?

[in-need-of-cash-too]

How long will/does ebay allow the buyer to return the item, from the time a buyer receives the item. Is it  10 days from receipt of item, 30 days, 60 days,  90 days.  Can/how does seller specify a set time frame (from date of item receipt) or is it ebays decision to force a return. 

[reallynicestamps]

The buyer has 30 days from receipt to open a Claim.

Then eBay and the seller send  Return Shipping* as soon as possible.

When tracking shows delivery (not shipping delivery) the seller should refund promptly, because if they don't, and the buyer complains, eBay may refund from their pocket and come after the seller for reimbursement.

Any further arguement, such as the condition of the returned item, should not hold up the refund. Which is sometimes a new and different problem.

*We can send USPS Return Shipping Forms by using Shippo.com. EBay may help with other shippers/countries, I'm not sure.