Airtel — sim not able to upgrade to 4g

Address:

East Sikkim, Sikkim, 737101

Its been 3 weeks since i asked to upgrade my 3g to 4g and yet its not able to upgrade i asked the store to help me with my issueand they told me to go to airtel office. They said that the sim registered was from a different person so i asked them to change it to mine, the people from the office told me to wait for 1 week and there is still no changes. I hate you airtel