Poor Customer Service and Speed

Recently my 240/120Mbps line has been throttled on LAN and WIFI network. I used the chat and spoke to Given, he ran me through things to do and reset the router. The LAN speed was restored but the WIFI signal being given out was 17Mbps and my phone was the only device connected. Given had closed the chat saying that the LAN is fine so they have resolved the problem! It is unacceptable that Given had asked me for what I believe the issue may be with the WIFI being weak! HOW CAN I GET ONLY 10% OF MY ORIGINAL SPEED! I understand that there is a drop in Mbps when connected to WIFI but by 90%, is just ridiculous! I have a feeling that the router is struggling to keep up with the demand or they have hard capped the router to throttle the wifi, the urgency to close the chat after mentioning that seems very *****! LOOK FOR OTHER ISP's PLEASE EVERYONE!