How to argue to the provider that it is impossible to connect links from several clients to one unmanaged switch?

Question

Computer networks

From the small-town provider comes optics to the point. Optics enters the converter, from which there is a copper link to a regular switch 5 port, unmanaged. (some kind of deshmansky type of length).
Two copper links come out of this switch - one to our point and one to a third-party client.
After calling the provider, it turned out that they consider this the norm. For me it was a little surprising, I'm used to the fact that after the provider's managed equipment I am the only client, for the first time I encounter the fact that after the converter there is an ordinary switch into which another client is plugged.
Well, by the way - constant packet loss at the point is already the norm, even in Zabbix the trigger was disabled.
How to convey to the provider that this is not allowed? Or am I wrong?
PS do not offer to change the dip, a point in a small town where there are not many options to change the provider, especially in the industrial zone.

Answer 1

Local providers everywhere use this. Especially those who grew up from the home networks of the zero and still sit on legacy equipment and technologies. For the local level and prices - this is quite enough. If you want a "Moscow" service - roll out the task and look for offers for the Wishlist. And this provider works as it works (well, either with the terms of your tariff / contract, it works like that). Under a different tariff, you may be given an L2 link or a personal fiber, but for other money.
Multicast in the access segment is not particularly present - there are only client routers, therefore, in any case, from the wan side, everything except your ppp drops and does not fall into your grid.
About packet loss, lags, etc., as you have already been told above, within the framework of the contract, you can make claims. Or still look for another provider: a small city / industrial zone is not an argument at all now. You can always find options from 3 / 4G, LTE, xDSL, WI-FI bridges, up to pulling your own optics to the PBX RTK or the point of presence of the desired wire.
It was you who simply did not contact the corporate departments of providers to calculate your wishes (any whim for the client's money)

Answer 2

Even in data centers, it happens that there is one vlan for several clients, and you want high technologies from a local provider ...

Answer 3

Yes, you can
. If there are problems with the quality of the channel, talk to the wire about this. Let him redeem. But even I don't think it's because of the switch