No Repair/return support from FirstShop

I bought a business laptop from Firstshop in September 2023 (With 3 year next business day onsite support). The HDMI port stopped working. On Monday 1 July I contacted Firstshop. The call center agent asked for the original invoice number which I supp****. She said the will gladly assist, but need the serial number of the laptop. She asked me to email the Invoice number and serial number, which I did. By Wednesday I received no reply and contacted the call center again. The agent said she will gladly assist, but I need to email the invoice number and serial number. I was informed that the first agent gave me the wrong email address and she gave me a different one. I immediately forwarded the previous email to the new address. By Friday Morning I recieved no reply and contacted first shop again. This time I was informed that Firstshop will not assist me at all as the laptop is older than 6 months. The call center agent then provided me with the support canter info of the manufacturer. I asked to speak to a manager as 3 call center agents have 3 different opinions and after 5 days I'm still struggling to get the promised next business day support. The manager was not able to speak to me at the time and committed to call me back before 13:00 on Friday 5 July. Obviously this has not happened, and I am at my wits end to get support from first shop.