You have to run the test by cable, not by Wi-Fi. 

@Ricardo27 Thanks, I tried using a cable connection and it seems to make little difference

What device did you use to perform the test? Which router do you have?

@Ricardo27 

Thank you for your reply.

With Wifi connected, I've tested it using my laptop, phone, and tablet and the speeds are almost the same.

I use a network cable to connect to my desktop computer and it's also the same speed as above, and I'm connected to a router provided by Meo.

The cable is at least CAT5e?

If so, you have to contact technical support to run some tests.

Yes, the cable is CAT5e.

Thanks for the suggestion. I'm going to contact Meo.

@Ricardo27