You agreed to pay $950.00 for 3/10/2019 to 4/10/2019. You paid $950.00 for 3/10/2019 to 4/10/2019. Just because you did use it doesn't change that.
The LL is violating the law because there isn't enough notice of an increase but that doesn't change what you owe for 3/10-4/10.

