... I agreed on the quote given to me, which included having the software, Android and IOS apps created. In the process of the developers developing the software, I learned the quote given for the apps, were highly over priced. In the beginning of the development stage I was told, "once the software is completed we will upload it to your server and once that is completed, we will then create the web view apps". Now that I requested for them not to include the apps (remind you, development is not yet completed and nothing has been uploaded to my server) yet I'm being told, the web view apps are completed and I owe the balance for the completed development of the apps. My question is, is it possible to complete web view apps before completing the software and uploading it to my server?
How much higher was your price compared to the average?
I haven't experience with webview in particular, but principally, software design is built around the concept of delegation - a system can be built with external call placeholders, assuming other systems will generate meaningful data in time, under a certain format specification (api). It goes all the way down to machine code, with linkers. Moreover, generic builds are easier to customise than writing code from scratch, so it's reasonable the former be completed before the latter.
That said, whether or not the apps are considered fully functional, is somewhat beside the point. From the developer's perspective, you've committed to a contract, and are now backing out of it, intending to undercut them severely; It's almost certain that they were aware that the frontend was overpriced, and it might have swayed them to take on the job. Whether they should have pointed out the pricing difference in the first place, that is debatable - indubitably bad business sense for a freelancer and a bit on the excessive side of honesty, sometimes the pricing's higher for a reason (though I take it they gave the price rather than the other way around? Might be a form of price gouging). Whereas on your part, it's entirely dishonest to alter the deal after the fact, frankly. They've expended at least some resources in development (you haven't mentioned exactly how long) and you unilaterally decide to trash that because you think you can get it cheaper.
Naturally, they will have resisted such a proposal. It doesn't matter what state these apps are in (and there are always bugs to correct with placeholder calls, ranging from minor to feature creep). Hence you've got a legal dispute on your hands. And nobody's gonna give you legal advice without inspecting the minutia of the case, because that's how a contract gets voided. You might be able to negotiate your way out, but I doubt it. Walking out of this with the software uploaded to your server, unrealistic expectation.
That thing you were told in the beginning, about the ordering of development - if in writing, it may carry some weight. I wouldn't know how much exactly.