I'm sorry to see that you haven't been receiving your expected speeds, I can certainly appreciate all frustrations with those results.
Upon checking the back end of your services, I have found that there currently are a few issues which are affecting your signal levels.
As this will require an engineer visit to resolve, I have booked one in for you at the next available date. You can find your time slot via your online account here. You can also rearrange the appointment time slot if needed from there.