Hello. I have just changed my old internet in Netia to fiber optic up to 300 Mb / s in the same company. The Internet is connected with the old twisted pair (which is the cable from the beginning, clasa 5s), and the TechnicolorTG389ac router. At the beginning there was a problem with speed, the technician decided that the cable is broken or there is no one wire and the speed will be at most 100 Mb / s. Cable for exchange. I was not at home, my son was present. After arriving I checked the speed on the cable and in popular tests, on the PS4 and TV samsung comes out over 200 (on the computer within 300 Mb / s) that is probably ok. However, after WiFi is poor in the 30-Mb / s range and jumps down hard. The question is whether to replace it, whether to manage it from the supplier, or to buy a better router that will raise my speed and stability / stronger signal? and if so, which one?