Avis not returning holding deposit due to staff incompetence.

My vehicle was involved in accident and i received a hired vehicle from Avis through Outsurance.I kept the vehicle for 2 weeks and returned it on Friday 31 May 2019.I had to give my bank account details and an amount of R1350.00 was deducted from my cheque account as holding deposit.Avis deducted R811.94 for petrol ,to which i agreed.My holding deposit of R1350.00 have still not been returned.I spoke to Innocent at Avis Strand a couple of times he assured me,he sent the request to my bank FNB.My bank stated that the release was not in effect as Avis never notified them.I lodged a complaint with Avis and contacted Mpilo again yesterday.He stated that the release was never authorized by Innocent, and he assured me my funds will reflect in my account by 13H00 today.Guess what my own funds have still not been released.Avis seriously lack proper business acumen ,and should learn to treat their customers with respect.I contacted the branch in Strand twice today, and the phones just kept on ringing.