Customer Dilemma: What to do?

The mango is in a dilemma with a customer on what to do in his case. Even gut feel is in two minds in this case. Request help to understand what best should be done in this case. Explaining the facts of the case below.

March 2013: An Indian in UK calls up mango helpline and sends an email that  he wants mango to UK. We reply we do not send abroad as yet. He asks Mumbai? We say yes, he places an order asking us to deliver green mangoes to his family, stating that they will arrange to send to UK. The order is for 5 dozens of the costliest mango. We categorically tell him travel to UK beyond Mumbai is on his own risk.

Mangoes dispatched in April first week and delivered in the next two days. No update or call or sms or email from him for 25 days. We assume all is well.

May first week, we send a blanket update email, in which among other things we write that we have replaced mangoes for all bad mango complaints and if any complaints are yet unaddressed, they can write to our chairman.

This guy emails our helpline three days after this email saying his mango was rotten fully and demands a replacement. He says he is late to reply as he was out of the country. 

 I respond saying it’s been almost a month since the dispatch and it was your risk beyond Mumbai. Do you have proof, like pics of mangoes.

He responds saying the mangoes had been turning black from inside the day they reached Mumbai. He does not have proof as he did not click pictures.

 I say the mangoes would have been still green and impossible to become black from inside. Why did you not call us there and then? He says see I am not asking for a replacement, just because you said you replace bad mangoes, I thought this is great customer service. I would not have asked for a replacement had the mangoes been good as I know this is a direct hit to the farmers. 

 He then threatens, subtly, saying he will not buy again, but will now tell others what has happened with him.

 Now the dilemma starts here.

We replace bad mangoes as a policy.

We maintain it was impossible for the mangoes, all five dozen mangoes as he says, to have gone bad in two days after reaching Mumbai. They were green and hard. How could he see inside? Did he cut them raw? Had the gone bad as he says, he should have called asap, and not after 25 days. There is no proof also now for it to be photographed. 

Mumbai to UK was not our responsibility and risk. What if mangoes were changed by the courier who took it from Mumbai? 

What if all was well and he is lying?

 On top of it his threat to badmouth us if we do not replace. Flipkart also has some cases where people put up pics that stones were delivered in the pack instead of mobile phone or tab. No idea how it responded.

What should we do this case?