There is nothing wrong with your data, except that you haven't uploaded very much for some reason - your last upload was at 13:09....
The resync events shown are correct, one gets generated each time you turn off/on your modem/router. They are shown as Reason 0 Loss of Service (LOS) events. That means the modem has to renegotiate the connection or resync it and resets the line Uptime it keeps a record of to zero. You can see this via the Uptime graph and it is that is used to work out the time of the resync.
The second one shown did change the Upstream speed, but there isn't always a change in sync speeds. The resync events won't show on your graphs as you don't have enough uploaded data yet (hover over the little blue icon by the checkbox for showing these and it will explain).
There are no ways of deleting data, it's all useful.