Charged for nothing done

I wish i have rather taken my car to agent the first time. The charged meR800 for diagnostics with no diagnoses given or they did not even check car i did check fluids myself the they than wanted to charge me further additional R3000 to diagnose car. we know the rand is getting tuff but really charging people for not doing anything I am sure consumer complaints will have a field day. https://mybroadband.co.za/vb/showthread.php/779251-Reasonable-price-for-a-diagnostics-test

https://axleaddict.com/auto-sales/What-is-a-diagnostic-fee-and-why-you-shouldnt-pay-it

https://budgeting.thenest.com/need-pay-mechanic-didnt-fix-anything-25180.html