Thanks so much for the insight, (and not so much for the smart-a$$ reply, we're really proud of you for learning sarcasm, must have been quite an effort for you to get all the words in the right order).
All I can tell you was that this was definitely not a wine. It was served cold out of a tap, was quite carbonated, and had more of a grape juice taste with the nice tartness of a hard cider and didn't taste anything like wine, dry or sweet. Your ideas definitely gives me a starting point for experimentation.
Call it whatever you want, and whatever the manufacturer called it. But it's not sarcasm to try to understand what you are looking for and to use terms that help us get there. We are trying to help, but not even knowing the brand of the drink or the make up of it makes it a bit difficult. Everyone getting on the same page with terms and what you're looking for can only help.
The fact is, "cider" means "apple". The definition of cider is "an alcoholic beverage made from the juice of apples".
There is no such thing as a "grape cider"- it's either cider (from apples), or wine (other fruits). Perhaps what you want is a low alcohol wine, or pehaps it's cider with some added grape juice. The same drink made with pears is called "perry".
Those terms are what we have to work with, but of course winemakers can do whatever they want to make a great and enjoyable beverage.
It sounds like you're looking for a lower alcohol grape wine, and to have it sweetened and carbonated. I wonder if they used something other than wine grapes- say, concord grapes or catawba grapes.
That would be the first thing to think about- apples are grapes are vastly different. Apples are high in malic acid, and most grapes are high in tartaric acid but some grape varieties are higher in malic acid. That's what made me think of concord or catawba type of grapes. They would be less "wine"-like in taste, and have a lower SG as well so they would probably be a good place to start, especially if you were sweetening the wine because they are very "biting" and acidic when not sweetened.
You can make a lower ABV wine, carb it up, sweeten it as desired and serve it out of a tap. It's still considered "wine" and not "cider", unless it's made out of grapes. That is probably hard for the maker to explain so maybe that's why they called it cider, however it would be just as possible for it to be apple cider with some grape juice added.
If you could find out what sort of ingredients they actually used (cider vs grapes), we can help you emulate it.
Oh, and by the way, welcome to the forum. We love talking about tasty fermenteds here.
Since you're new, I'll just try to politely mention that the only real rule we have about posting is "don't be a dick". Being sarcastic with a "thank you" like that does border on that, so try to be skip the sarcasm yourself. It's hard to convey things in typing vs face-to-face, but please keep it in mind for next time.