Really disappointed…

Upgraded my package to 1gb broadband. Ever since then my broadband been running really poor. Don’t get above 300 an all devices. Had an engineer come out, said the signal was bad, changed the port and gave me a new router and was told there was work going to be done outside my house. I got in touch with customer devices to explain my speeds were still bad and to ask if the work was done outside my house and said they were sending out an other engineer, but nobody showed up. I seem to be just going round in circles here. Very unhappy customer.