Nedbank Incompetence

In February 2018 i received a call from nedbank loan department inviting me toapply for a personnal loan of R200k they did an assessment and email me the preapproval quotation. i didnt need any money buy then so didnt apply for it. on the 03 April 2018 i went to cash build to buy the building materials so I decided to apply for a nedbank account inside the cashbuild(BDO) I was approved for R200k cashbuild account by nedbank. after assess what i was looking for i decide to take R100k which was approved. after 23 days when the account was used we realised that there were still other materials short to complete my house. i went back to nedbank to get the limit increse. nedbank decline my application they said "the applicant cannot be self employed" so aquery that because my employment status was not changed wuthin the time period i apply for the loan and when i wanted the limit increease? so I query the criteria used with my loan application granted at first working for the same employer and 23 days later nedbank say they errously approved my application. so what kind of incompetency is this with so called major bank? i receive my salary through nedbank and i am employed?