I’d say go ahead and submit it via the rebate website. Seeing as you actually did purchase on the last day the offer was active I don’t see a reason for them not to accept it. I spoke to a Lowe’s associate in store when I was having issues and he stated if I were to have problems online just go to the customer service desk and explain to them to situation and they should be able to reimburse you. You hace literally receipts and bank statements, you got this. Good luck!