You pay for 50mpbs but will only get 30mpbs

Can you guys please tell me how I'm getting 4mbps and 6.62mbps on a 50mpbs line? Am I doing something wrong or does this mean you guys say up to 50mbps meaning you will charge me full price but you not going to give me what I pay for you will give me maybe quarter speed so you pay for 50mpbs but we will give you like 26mbps and yes I have the screenshots to prove it as well