Broadband only 15mbps - What can I do?

Hi folks,

I have bought an apartment at the beginning of the year in Balbriggan and I started looking for broadband but to my surprise whenever I clicked my address I only can get around 15mbps. My neighbour next door in the apartment block is having around 100mbps with no issues. So, I gave a try to SKY - but it really is around 14mbps. They told me that it is maximum that my line can accept ( how my neighbour have 100? ). I thought that it is just 1 cable that is being connected to the block and then via splitter it is being redistributed to particular flats. So there must be something wrong with the connection/cable to my apartment. We have two boxes on the ground floor:

The first one I think is fiber splitter but not connected to anything. Also I have checked a map for siro coverage and everyone around have Siro apart from us:

Sky says there is nothing they can do, I have contacted Siro - no reply. Contacted Open Eir via twitter - they replied that they will look into it but it takes already some time.

Is there something I can do? someone else I can call or invite to take a look at it? I am very frustrated with those speeds..

Any feedback would be highly appreciated..

Thanks!