Bad service

I have called Balwin connect on multiple occasions about my wifi speed being slow and disconnecting. Each and every time I call, they advise that they're escalating to the fibre department and yet nobody comes back to me. This is absolutely ridiculous. The level of service is putrid. How many times do I have to escalate the matter? At what point is this going to be taken seriously?

I've even had my router and ONT box changed to have this issue resolved. I'm paying for a 500mps line, yet my download speed is 38mps. What am I paying for?