ZipCloud may be a cloud storage option, but with a somewhat dubious reputation.
I get the same slimy feel from that as I do with MacKeeper (another one to ignore, if you can

)
If you search for ZipCloud, you can often find both ZipCloud and MacKeeper mentioned in the same articles.
Here's a
page that may help you out.
It describes the same popup that you are seeing, along with how to remove it.
I would suggest that you also download and run the free utility
Malwarebytes.
Again, if you do a little searching, ZipCloud may not be malware, but it seems to travel alongside malware - another good reason to move it out (away from you!)