Insurence damge my phone and force to pay R1000

After buying a new a20 and insuring it.on the 3rd day my phone fel flat on the face and screen craccked .sent it to edgars for a claim to have it repaired.after 3 weeks they sent me an sms saying to come and pay500 for the excess.so i go in to the store.now i get my phone ....screen looks good but the back of the phone is so damaged and scratched and to top it off they tell me they made a mistake its not 500rand but indeed 1000. After i try to state my case they dont want to hear nothing so the sms was a mistake? But i planned according to what my insurance said wich was 500rand.now they want to send my phone kn for another 3 weeks to repair the back? I cant be with out a phone for another 3 weeks .im a rep and depend on my smart phone for doing buisiness sonalready lost 3 weeks of money no they exspect me to loose another 3weeks because the messed up my phone??? I even took photos the day i got my phone back what a dissapoint ment