Ongoing ***** case

It’s been over a month and 3 weeks now! My partner sold a few products to a customer, the customer paid and sent proof of payment, about 30 minutes later he ( the customer) called fnb claiming he sent the money by accident and reported it as a ***** cause. My partner has called and emailed countless times- he’s even gotten a case number, at this point he has tried everything and the bank isn’t co operating, they keep saying they will give feedback in 48 hours which turns into weeks of no response. Yet the person who reported this refuses to go to the police station or call the bank. As a loyal customer to fnb this is very disappointing very. My partner has been struggling because they froze his personal account ( which includes his saving) and business account. Again this is extremely disappointing!