For the given scenario, you can remove or delete older snapshots under which unwanted data was backed up. Step by step process to delete snapshots is given on the following documentation page:
DISCLAIMER: Deleting a snapshot will permanently delete the relevant snapshot data and is an irrecoverable option.
Post deletion of a snapshot, the relevant cloud storage space will be freed up after the compaction process runs, which is responsible for purging these data blocks.
Additionally, to avoid unwanted data from getting backed up, you may consider configuring appropriate include and exclude filters under the profile. Please read more about Include Files, Exclude Files, Exclude Paths and Global Exclusions on the following page: