Tempest declining service

Pathetic Service Hired a vehicle from tempest OR Tambo 05/11/2020, duly returned the vehicle, Tempest was unable to supply the vehicle i booked, i supposedly was given a replacement vehicle at "No additional Cost" , for which i was charged EXTRA, NOW almost a month after returning the vehicle, Im struggling to get the deposit back that i Paid for the vehicle. I am 71 yrs old, i am a pensioner and i dont have the means/time to run from pillar to post For TEMPEST to get my deposit back. have tried calling your customer care, to no avail....Never had a problem before with Tempest before, pathetic service this time round.