Issue with restoring files from older back ups

Hi

I am hoping that someone has had a similar issue and can advise us how it was resolved.

We used to use Norton on-line back up (NOBU) and this allowed access to all previous back ups and allowed, if/when it was ever necessary, for an indivdual file to be restored from a specific date - a function that we need to have.

In February 2015 we took on Norton Security with back up (NS) and soon discovered that oddly within that software we could only restore a file from the latest back up and not from one that had been carried out prior to that.  We still had a NOBU subscription and fortunately discovered that through that (even though we couldn't through NS) we were able to specify the particular date of a back up that we wanted to restore a file from - we have for that reason kept that subscription open even though we originally expected NS to replace it.

We have been using this facility and fortnightly checking that it works and have now found that something has recently changed which means we are unable to access the old NS back ups.  We can still access back ups up to February 2015 and we can access the lastest NS back up but not the NS back ups carried our between February 2015 and the latest one.

We have a list of computers on the NOBU home page and the one we used to use for this has for some reason seemingly disappeared.

Can anyone throw some light on this issue?

Steve