Horrible service. Non refundable

A while back i opened a contract with vodacom, for the new Samsung S8.. After collecting my phone i decided to buy some protective accessories from their store. I bought a protective screen glass costing R300 which they offered to fit for me. I agreed to let them do it as i assumed they knew what they were doing. Apparently not, because when they handed me my phone , there was glue all over the screen and i could barely read anything on the screen. I then asked for a refund since i was displeased with it, only for them to tell me they do not accept returns. To top that off, when i got home and took off the protector, i noticed the screen was severely scratched from when they tried to clean it.

This surely cant be fair?

Only thing i can say about this is be careful when handing your devices over to them, they most likely have no clue with what they are doing.