Datasafe backing up at the wrong time - driving me nuts!

Subscribed to datasafe to keep my data backed up online. Set the time setting to GMT as based in the UK. Set it to back-up overnight. Tried the 6pm to midnight setting but it kept backing up at the wrong time. Tried the midnight to 6am setting. Last night it should have begun the back-up at 3am and been finished by the time I got to work but it actually started at 7.20am . was only 73% of the way through by 9.30am so had cancel it - again! Getting really fed-up with it as I need the pc working at full speed during working hours and this slows it down to snail pace! Any ideas welcome please - before I ditch it. Can't even ring up or email support as my pc is over 3 years old, even though the software has only been installed a couple of moths. I think the customer support on it is extremely poor.