R1059 disappeared into thin air...

On 23 March my husband used his credit card to rent a car from Thrifty in Cape Town, they blocked off an amount of R4000 as a holding deposit. We have proof of this and so does Thrifty. There were total charges of R108 charged to my husbands credit card, on 30 March he receives a reversal of R2941 from the R4000 that was blocked. He contacted the private suite, the lady confirmed this amount and stated that that was the authorised amount to be reversed. He contacted Thrifty in Cape Town and the head office in Kempton Park, they confirmed that R4000 was blocked and R4000 should have been reversed as they did not authorise any charges. So where is the R1059 thats missing. He has contacted 5 different people at 5 different departments at FNB, who all gave my husband the same answer, sorry we cannot help you, call the rental company. I then speak to a very helpful lady at Thrifty that does the accounts, she eventually got a hold of Sechaba Pholo at FNB who promised further investigation and will provide feedback to us by Fri, 5 April. It is 7 April and still no word. The guy whom she spoke to confirmed a R4000 block and a R2941 reversal. So if there were no charges on Thriftys side, where is our money? My husband is a Private Wealth customer and has never ending issues with his account. FNB refuses to be held accountable for money that they have 'misplaced', your slogan should be 'How can we rob you'..