Have you already resized the underlying block device (xvda)? If so then resizing the filesystem depends on its type.
If its ext4 then you can do it online without powering off your VPS. The command is
resize2fs /dev/xvda
If its xfs then you can also do it online with the following command
xfs_growfs -d /
Are you sure that your filesystem lives in a partitonless device?
* EDIT *
I just noticed that your filesystem is on /dev/xvda1 partition.
That means that you have to extend the partition size before growing the filesystem. This cannot be done online you have to start your VPS in recovery mode and then use parted to grow your partition so it can fit the new underlying block device.