Pathetic Refund Policy

I had purchased a Targa Thump Series 4000watt amplifier for my car in April 2015. Within a week of usage the amp had went into protection mode. I had taken it back to Govan Mani Pavilion to repair as it came with a one month warranty. It had been fixed and i had it fitted back into my car. December 2015 it had went on protection mode again, i proceeded to take it back to the store for repair. Again, i had it fitted back into my car. In February 2016, once again the amp had gone into protection mode for the 3rd time in under a year. I took it back only to receive a call in 5 days stating i should come in for a refund as it cannot be repaired. On arrival i was told i paid by card i will be given a credit note which is absolute bull! I paid using a credit card which is now paid off and the account closed. When i paid for the amp initially i did not pay the supplier with a credit note. I think this policy is utterly disappointing and the sales consultant was abrupt and rude about them not being able to refund cash. Also they did not consider the inconvenience of me having to come in mutiple times because of their faulty stock. PATHETIC CUSTOMER SERVICE.