Help required against Nedbank Insurance ****

My first mistake was buying a bank repossessed property. The second (and larger one it seems) was buying it through Nedbank! We were forced by Nedbank to follow the legal route and have the then occupant evicted. It transpired however that he vandalized the house 7 property and then called us to collect the keys on 25 July 2018. We put in a claim for R943,111 in damages to the property - Nedbank paid out R99,908.43 citing that the property was under-insured and there was no forced entry as reasons for not paying, To date the y are unable to produce this alleged valuation report from their valuator, and want to put my house value up by almost one million rand (having also between all this managed to come to a valuation of 1.9billion which they have never even bother apologizing for). Do I have recourse? I know this is beyond the prescribed length of time that is allowed to elapse - but they are totally inept and have shown nothing but apathy and incompetence every step of the way. Someone with legal "oomph" please respond?