I purchased a Sony FE 35mm f2.8 lens from amazon.co.uk on 18 June 2018.  According to Sony, this lens qualifies for an £80 cashback.  I submitted my claim 30 days after the purchase date on 18 July 2018.  The claim contained my invoice and a photo of the lens.  However, my claim was refused with the message: "It appears that the date of purchase is the 21st of May while the claim was submitted on the 19th of June."  These dates have nothing to do with my purchase.  The messages on this forum suggest that this is not a one off mistake and that Sony seems to routinely refuse legitimate claims.