help with a electrical item repair problem

mathew1234

Hello my aftermarket car radio recently developed a fault where the front panel was making a heavy rattle while driving. i first contacted the store where i purchased it from as it was still under its 1 year guarantee and they said it would have to be sent of for repair so i agreed to have it repaired. 2 weeks later i received a latter saying that there was no fault found and that i would have to pay £30 to get the radio back this was to cost of wasting there time. I then paid the costs and got my radio back which still had its very annoying rattle. As i was not happy i contacted another authorized repair center and asked if they would have a look at it and they agreed that if a fault was found it would be fixed under the units guarantee. When i received the unit back there was a latter saying the unit was fixed and a receipt with the parts they used to fix it and it no longer rattles.

I was wondering do i have the right to get my £30 back and what do i do if they refuse?