What a shock for you auntieAnnie, but if the mum is now settled with her babies, just feed and water her and stay away from the babies and she will do the rest. Take a note on your calendar of the day/date the babies were born so that you will know when they are four weeks old. How many babies did she have?
This is the risk of buying a small pet/pets from pet shops as they can be useless at sexing them and can have them co-habiting well over their reproduction age.
Just make sure the mum has plently of safe, paper shredded up bedding (NOT that woolly kind) as thin can get tangled up around babies limbs and cut off the circulation. Extra protein like mealworms for mum and a nice piece of fresh apple (remove the pips).
You cerainly should give the store a telling off as chances are they won`t change unless they know this has happened and someone else could end up with a pregnant female. If they ask to buy the babies back, refuse. You can always find them private homes or keep them yourself until good, safe homes can be found.
Edited to add: If your cage has tall floors, a syrian really needs more floor space than height, so once the babies are old enough, I would suggest looking for a larger, longer cage/tank for the mum. Same for each of the babies once they go to new homes or need housed by themselves.