The easement gives them the right to do the work without your permission. But it does not give them the right to damage your property. You should be able to recover the cost to redo/replant the flower bed, fix the driveway, and eliminate the leak by suing the contractor (you should name both the contractor who did the work, if you know who it was, and the cable company in your suit) for their damage, done deliberately and/or negligently (unreasonably carelessly) to your property.