Media Converter D-Link DMC-G01LC

[Subtitles]

A friend had fiber internet and streaming TV for about four years. He had his own router so he didn't need to pay a monthly fee for the use of the router, but they used a little box D-Link DMC-G01LC fiber signal to Ethernet. He paid a fixed price which apparently included the use of the media converter.
Few months ago he decided to cancel the TV package and to keep only the internet. In the latest invoices they started to charge him about $1.5/month for the D-Link box. He was a bit surprised because he has been paying for it for over four years but they didn't tell him there is a hidden cost.
He asked for my help because he is hopeless with anything technical. So I bought him the exact D-Link model yesterday which costs $25 and installed it and everything is working as before. So now he can return the box to the service provider. The only problem is that the fiber cable connects to a SFP transceiver which is inserted into the SFP connector on the D-Link media converter. The one I bought came without the transceiver so now I am not so sure if they will accept the return, or ask for the transceiver as well. In the invoice they only mention the DMC-G01LC so if the transceiver is part of the use of equipment, then they should have added the exact model in the invoice.
This is another example of how these companies maximize their profits. Obviously they bought enormous number of the D-Link box so my guess it cost them about $10 maximum including the transceiver. Multiply that by at least 100,000 subscribers, each one paying $1.5 a month which is not a bad investment on this little gadget.
Ok so my question is this: Do you think that he should also return the transceiver, or this can be considered as part of the monthly payment for the internet?

[zing269]

SFP modules are fairly cheap, around $10 - $25. The original one should be marked as to what type of fiber and what wavelength, make sure you buy one that matches.

[Subtitles]

SFP modules are fairly cheap, around $10 - $25. The original one should be marked as to what type of fiber and what wavelength, make sure you buy one that matches.

Thanks for your reply.
Yes you are right these Gigabit transceivers cost about $10 and I can easily buy them from Aliexpress. But my question is if you think the service provider will insist on returning the transceiver as well, or this is part of their "internet" deal. I would be surprised if they will ask to return it because it has been working for over four years and they can't use them for a new customer because they are supposed to install everything new.
Returning the equipment is a big hassle now because they closed the one that was near and now we have to go to another city to return it. So if they ask also for the transceiver then we have to travel again.

[zing269]

I doubt that whoever is receiving the returns would notice it, but if your providers are anything like ours they'll charge you several times what it is worth if they do notice it's missing.