Provisions fund / service charge

Neetneets

I am a housing association tenant with an assured tenancy. I have lived in my house for 29 years and on receipt of my new rent charges notice for this year I noticed there was a service charge added to my notice as well for the first time ever. It says it is for a provisions fund. When I called to ask for my information about the charge I was advised it was for future works. I am not sure if I am liable for the service charge as it was not on my tenancy agreement. When I call or email the housing association noone can explain clearly what the future works are or what the charge is for. I am happy to pay my rent but am worried what might happen if I don't pay the service charge. Any advice or help appreciated