Gigantic Infotel - Poor Internet Service

So ,I moved into a new place out of delhi .Where I got internet installed and for that internet I took the plan (**mbps)from my isp and on the second day after installation on internet I called my sip regarding the speed issue and from the date they have taken no serious action to my complaints .whenever I call them they reset my internet from there node and then my speed gets fixed for ** minutes and after that it get back to what it was which is like *.** mbps to *mbps They are also using the speed limiter at night after **pm the speed drops to *.* mbps which is of course no a acceptable speed for a ** mbps plan. So as of today which is **st April **** , they send there technician at my place to fix the internet and as always when the technician came and the speed was okay as they reseted my internet and I even asked the technician to sit and watch the speed drop after ** minutes which he refused to and said there team will call be back after **minutes and as of this time I haven't received any call from there team .I also email them with screen shot that as there technician left the speed dropped again to which they are saying "As per your concern, our person recently visited at your premises and he has checked your connection is working fine.And on your last mail our team has checked on remote access on that time it was also fine as per plan."(screen shot also attached ). and even inferno too the technician the speed dropped to ** mbps which would be in his laptop in speed records test results (I have attached all the evidence do check it out as I was only able to attach one screenshot it would be really helpful if I could share evidence through a email id).
Thank you