Good day Fellow Sparkies

I have recently repaired a geyser at a big business,it was the element,I charged them the following:

Element R135
Labour incl. travelling 3 hours @ R300 p/h

Total : R1035.00

The business is 30km from my office,I got questioned whether that is the going rate or not,was I under invoicing or over,please advise...

Regards

Colin