Need help with infuriating dedicated fibre line setup

Hello, we have a bit of an issue with a leased line (a dedicated fibre to the premises line) which has been setup for our client.

The provider has run the line into the comms cupboard and they've provided a box which is the edge of the network. We have no access to that box, but there is an SFP+ port where the line from the outside world comes in, and a little green light to indicate that it's live, and an SFP+ port for the internal network access which also has a little light which is red to say it's not happy (this is the infuriating part).

They did provide a transceiver already in the slot, but there was some confusion about that so I've also ordered several other options, some of them customised from fs.com for that specific model. Anyway, on the other side we've got a Draytek Vigor 3910 which we want to use to run that WAN connection via it's SFP+ port, and also a second connection which will be a failover.

The leased line provider has given me the following details:

WAN Subnet xxx.xxx.xxx.0

or 255.255.255.252 depending on who you ask from their team

WAN Subnet Mask /30

WAN IP xxx.xxx.xxx.2

WAN Default Gateway xxx.xxx.xxx.1

​

Routed IP's Network Number xxx.xxx.xxx.44

Routed IP Mask /30

Routed First Host xxx.xxx.xxx.45

Routed Second Host xxx.xxx.xxx.46

Routed Last Host xxx.xxx.xxx.46

Routed Broadcast Address xxx.xxx.xxx.47

DNS servers xxx.xx.xxx.12, xxx.xx.xxx.6

​

Now I'm a total novice in this particular area, and I can't figure out if I'm doing something wrong, but the access light on their box will not go green. I'm confident that it's not an issue with the transceivers as I've tried so many different options, and in every case the light on our Draytek is green, it's only red on their box.

In terms of the network settings, on the Draytek I've configured WAN 1 to use the SFP port with the following details:

IP Address xxx.xxx.xxx.2

Subnet Mask xxx.xxx.xxx.0 and/or 255.255.255.252

Gateway IP Address xxx.xxx.xxx.1

DNS servers, as above or 8.8.8.8, 8.8.4.4

And it just doesn't work. But then there is something else that worries me, all that stuff about the routed IPs network number with the 2 usable hosts, what's that even for? Is that where I'm going wrong?

The providers support has been less than useless, honestly the worst I have ever experienced. They really don't want to help troubleshoot the issue, basically they're happy for the line to never ever be used and apparently that's the end of it because they're confident that the issue is on our side, because they've run the same stupid test over an over which shows that the access status light on their equipment is red. So I implore anyone who actually knows about networking, have I actually used the details that they've provided correctly, or is there something really obvious that I'm missing, or is it all about that second set of details with the routed IPs?

Thank you so much to anyone who can shed some light on this.