Leaseholder issues with freeholder?

Hello, I am the leaseholder and I am having issues with the freeholder who rents out the flat above. The tenants are noisy because of the wooden floors and there have been two leaks which have caused damage to my flat downstairs. The freeholder pays a letting agent to manage the property upstairs.

In terms of the lease, the freeholder must pay the house insurance. When I moved into the property I contacted them about the insurance and they never got back to me so I have paid the house buildings insurance for 4 years even though it states in the lease that they should pay it.

They have not repaired any of the leak damage and after saying they would install carpets they have not done anything to the property.
I have also had to contact the insurance company as we have movement in the corner of the house and they will have to pay for the excess but I am not sure they ever will!

I am not sure what to do. I have maintained the property and cleaned the communal porch area and front garden and painted the outside of the house with no support from the freeholder.

I am looking for some advice please,

Sarah