Lufthansa — Handling of flight disruption

I have booked two tickets from Austin to Bengaluru for 27th July 2022. The booking id are: 5T27RN, VXGDXX.
There is some strike on the day and the flights got cancelled. So instead of refunding, they provided alternative flights (of other airlines). This was arbitrary, without even consulting or giving options to me.
On top of it, the original ticket had 2 pcs of free luggage from Austin to Blr. Now the rebooked tickets from Austin to Chicago leg with United Airlines seem to only have 1 pc of free luggage. United Airlines is saying that when the ticket got rebooked, that is the information that they got. The rebooking was done by Lufthansa and no one is picking the phone to enquire about this.
Now I am having to pay Rs. 20000 extra for my luggage!
I request an that Lufthansa immediately to compensate for this.