Refund Issue
First time posting so let me know if something is wrong, also posting from mobile so sorry if the format is weird, also sorry this is a little long. I need some advice on how to handle the current situation I am in.
I am selling a Moc on Rebrickable (Spider-Verse Apartment Complex) that is a Moc that combines five other Mocs I made. It modifies the Miles Morales vs Spot bodega (set 76311) into a modular building and then has four apartments for various Spider people on top. One of the apartments is a modularized version of the Peter Parker Apartment (set 76317) and two others are inspired by the apartments from the Oscorp set (set 76324). In total the Moc is 2662 pieces. I have sold the Moc 44 times and have had no issues before now minus some recommendations to update the Moc and tweak instructions which I did.
The issue: I had a buyer buy the Moc, they downloaded the instructions, and then a few hours later messaged me a refund request. He stated that he believed the Moc was buildable only with the three Marvel sets (76311, 76317, and 76324) and this is “obviously not the case and misleading”.
Looking at the Moc itself compared to the sets would tell you this isn’t the case.
The piece count for the three sets is 1585 pieces which is 1077 pieces less than the MOC (this includes the Oscorp pieces which you can tell are not used in the Moc at all).
I have an entire paragraph at the bottom of the Moc’s description that explicitly states that most of the pieces from 76311 and 76317 sets are used plus additional pieces. I also explain how to find what additional pieces are needed cause due to the size of the Moc and the time it took to make it I couldn’t make the part list only the additional pieces.
I, also, state at the top that the Moc “uses most of the pieces from 76311 and 76317” and that “76324 is used only as inspiration” due to the low number of pieces that I took from the set.
They have already downloaded the instructions, which per Rebrickable policy gives me the right to deny their request without the previous information.
Ultimately, given all the information what should I do? Should I refund the buyer even though there are multiple reasons in the Moc description and logically why his complaint is invalid? If I don’t refund them, how do I let them know I am not refunding? Do I just reply to their message explaining why I am not refunding? Sorry, I have not had to deal with a refund request before. Also, if I do deny the request what is stopping them from making a PayPal claim or chargeback. Any help would be appreciated.