Vodacom not performing

Vodacom cant solve my internet speed issue. It seems like they are throttling the 4G networks download speed, my signal strength is 90% but i cant get more than 1Mbit/s on google speed test. I phoned numerous times and restarted my phone like they told me but nothing works. I'm having this problem with three vodacom numbers. I have big data contracts with them so i rely on sufficient download speeds. I will have to search for an alternative network