Slow Internet download speed

I called their call centre on 7th Oct and was given ref number ********** 1 to report the slow download speed on the new device that I got after upgrading my contract with them and got told that it will be sorted out before the following week ends as their technicians are not working on week ends. I called after the week had passed without any call or sms at least to let me know that they are working on my problem and was told that my query is still pending. Today 20th Oct I called once again and spoke to a girl who was clueless as to what is happening. Can these people please start taking customer serious or they will lose customers with their sloppy service or lack there of.