Vodacom bad service and bad insurance

Good day i have taken out a contract with vodacom about half a year back they gave me a device and sim card. which because i already had a phone which was in for repairs at the time so i used the new vodacom pone for only a sort while. In august i took out the deal they had for 300gig data for 299 per month. At the time i did not have a router so i asked the store rep what i can do what is the prices on their routers etc. She said she will come back to me i had her whatsapp number but she was always busy or on leave. in the mean time she said to me that i should use my second phone as a router, which i should hot spot from. I did so while i was seeking for a router at the best price.

Unfortunately my phone got lost and now i have to claim from the insurance. The insurance have now let me know that the claim has been declined because of the fact that i had used the other sim in the phone.

Why did the rep then advised me to this if she knows that it will void the insurance. They just casualy said it is declined while you must now pay almost 600 rand for nothing because your device is gone. they deduct insurance then for what is this insurance for the device or for the insurance? if the sim got lost would hey then give me a device for a lost sim or what.

I have previously claimed from MTN and i never had this happened