Experienced the same thing.

Ask if it was the same technician who did the reset. Mine wrote in his report that he reset it to 1.0Mb but it was only at 512kb the whole time. (Lesson: the technicians do one thing but write another. Makes me wonder how smart one must be in order to be working for TM.) Ask to change the technician in which they would not bother.

Leave it for one day. then check again. If it is still the same, make a beeline to your TM Point shop and ask to speak to their manager. You don't have to talk to the officers at the counter. I did mine quite rashly and am not that proud of it but it seems to work since when I shouted, they took me to the managers room to talk. After that, just tell the manager your problem and what the idiots the support side are being. If the problem was as per above in which from what you wrote seems like it, it'll take 2hrs the most to be done. Do make sure to highlight that you want a more experienced technician and not the current one that was assigned to you.

After that, and it's been bout 6 months already and my line is still problem free.

Hope it helps. Did not mention much details but really had a 'nice' session with them. I think I'm already blacklisted by them because of some of the things I did and said.