Certainly. Based on the provided legal document, here are the key points summarized:

1. A registered power of attorney can only be canceled through a registered deed. The court emphasized that cancellation by unregistered documents or notices, such as notices under certificate of posting, is not legally sufficient to revoke a registered power of attorney (!) (!) .

2. The sale-deed executed by the power of attorney holder was found to be valid, as the authority under the registered power of attorney was never legally canceled or withdrawn before the execution of the sale-deed (!) (!) .

3. The burden of proof regarding cancellation of the power of attorney and the validity of the sale-deed lies with the party asserting such cancellation. The court held that the plaintiff failed to prove that the power of attorney had been canceled before the sale-deed was executed (!) (!) .

4. Service of notice for cancellation via registered post or certificate of posting was not conclusively proved, and thus, cannot be deemed legally effective to cancel the power of attorney (!) .

5. The court reaffirmed that a registered document affecting rights in immovable property can only be canceled by a registered deed, and not by unregistered notices or other informal means (!) .

6. The appellate courts correctly appreciated the evidence and legal provisions, and their findings that the sale-deed was executed under valid authority and that the power of attorney was not canceled are well-founded and cannot be disturbed in a second appeal (!) (!) .

7. The appeal was dismissed, affirming that the sale-deed executed under the authority of a valid, uncancelled registered power of attorney remains legally effective and binding (!) .

Please let me know if you need further assistance or specific legal interpretations.