N1 City Incredible Connection - Bad service

I bought a Lenovo computer at Incredible Connection N1 City. While it was under guarantee it glitched for few seconds and stopped. A week later, it did the same and this time my daughter took a video. The sound was also affected. On the 27th May 2024, I went to N1 City to understand the process. They wanted the receipt which I could not find. I gave them what was on the box to trace them, they told me to go to the bank to get bank statement. At the time I am not even sure which card I used, and the bank needed the date, but we struggle to remember as it was about 11months back at the time. I went back and I asked them to check using the serial number and I gave them the time frame and the manager, refused to help me. The store at the time was not full and I felt they did not want to help. I lost it and I asked them why they ask us to keep the box if the information cannot be used. After screaming match with the Manager. I left and less than 5 minutes they called me that they have my receipt copy and I must bring the lap top the same day. I rushed home and brought the laptop. They told me that it will take 21 days. I requested that can it be quicker since my daughter was going to start exams on the 14th of June which was in 17 days. No commitment was done. On the 12th June I received a call with a quote that the screen was broken, which was odd because the screen was not continuously glitching but like I said it happened twice in a space of a week and a half. I then ask them to pack the computer back to N1 city and will collect. They told me that the computer will return in 5 days, it has been 14 days. Up until now the 26th June, no communication.