Inconsistent Speeds and Worst Customer Service

I wish there was a zero rating! I have with Net Nine Nine for over 3 years and they at ther worst they have ever been. I pay for 850/850 line but currently lucky to receive over 300 download and over 50 Upload. This has been going for for over a year and they keep blaming Evotel the fibre line provider. And Evotel keeps blaming Net Nine Nine. Evotel have checked my line and did various tests as per their requirements but have found nothing wrong. They are in constant communication and happy to try everything to assist me. Where as Net Nine Nine resets ONT etc then say Evotel must sort. They don't take any responsibility and it seems this is daylight ******* as they seem not to care or deliberately not giving the speeds I am paying for? I am really tired and frustrated now!!! Is there any legal way that I can pursue this as I cannot keep paying for a 850/850 speed and keep getting a quarter of that or less. I have made many complaints but no one dies anything. Customer Service is non-existant. Any recommendations for a better ISP provider? Right now anyone will be a 100 times better than Net Nine Nine. Unfortunately i have been patient for over 2 years hoping they would sort it out but i have had enough.I will not recommend them to anyone!!! I promise you you will suffer the consequences!