I was ****** and humiliated at The Glen incredible connections

I bought a phone when I get home I played music it was like I'm in phone call where there's no network connection so 4 days after I bought it I went back to the shop hoping they'll help me but the manager "Juda" if I'm not mistaken acted as if I'm mad saying I should play music in front of him about 30 minutes so he'll see if the phone has a problem,I referred to the invoice that it says I have a right to change my mind and right now I want to change the phone as it giving me trouble,he said he'll book it for service I said but it hasn't been up to 7 days so I should be allowed to change it without any issues,he refused.i then I asked to top up and take another phone he then said I should also pay 5% so it will be the difference cash between the phones plus 5%.i paid it coz I needed a phone but I was ****** and humiliated at incredible connection The Glen