EBay - withdrawal from purchase agreement, how to implement?

Ca
1

I have a eBay via eBay for the amount of 600, - € most likely to a "non-payer" auctioned.

After the case is closed on eBay and the buyer gets his note and I get my commission back, eBay recommends that the purchase contract be annulled in writing. Only by requesting payment, then again by a termination of the sales contract after not receiving the payment.

Which deadlines do I have to pay attention to as a private seller?
How do I formulate the request for payment?
Is a mail via eBay sufficient, or do I still have to do that by mail (with registered mail)?

op

The termination of a contract requires the text form or the written form.

Text form means that the terminator must communicate in writing that he terminates the contract and for what reason.

Written form means that a signed letter is necessary.

The former can therefore also be an email that can't be signed by hand. But you can't always end an internet contract with an email. On the safe side you are with a signed letter, which is also sent via registered mail / return receipt.

The deadlines that are set, you can set yourself. However, these must give the contractor enough time to respond appropriately to the letter.

However, you should refrain from threats or attempts of legal instruction. This would unnecessarily play cards in the hand of the other party, possibly with the result that the termination becomes ineffective due to a form error.