I think it will not work buddy. You need two telephone lines. It's not because of bandwidth. It's because you need two accounts. You currently have one account that you use on that one box, but where will you get the second account from? I'm guessing they don't allow the same account logged in from two devices at the same time. And perhaps they only have one account per line rule.
If that is not the case, then just call PTCL, tell them you lost all modem settings and tell them you need to setup your TV again. Don't tell them you want to setup two TVs or anything.
When I setup my TV, he asked me to setup modem setting connections like shown below. These are two connections, one of them is for TV and the other for internet, don't know which is which (this is what I was told, maybe I'm wrong). this was in the modem setting area for "WAN". Perhaps you just add another one of these connections for TV and then you have two connections and then it should work if everything else allows it.
[TABLE]
[TR]
[TD="class: hd"]PVC Name
[/TD]
[TD="class: hd"]VPI/VCI[/TD]
[TD="class: hd"]Category[/TD]
[TD="class: hd"]Protocol[/TD]
[TD="class: hd"]NAT[/TD]
[TD="class: hd"]WAN IP Address[/TD]
[TD="class: hd, width: 50"]Edit[/TD]
[/TR]
[TR]
[TD]pppoe_0_103
Disconnect
[/TD]
[TD]0/103[/TD]
[TD]UBR[/TD]
[TD]PPPoE
LLC/SNAP[/TD]
[TD]On[/TD]
[TD]Automatically Assigned[/TD]
[TD="align: center"]
[/TD]
[/TR]
[TR]
[TD]br_0_102
[/TD]
[TD]0/102[/TD]
[TD]UBR[/TD]
[TD]Bridge
LLC/SNAP[/TD]
[TD]*[/TD]
[TD] *[/TD]
[TD="align: center"]

[/TD]
[/TR]
[/TABLE]
So just call PTCL helpline and tell them you lost modem settings for the smart TV, they will talk you through to making a new connection for the TV.