I really feel you on this, it can be so stressful trying to figure out compatibility before you buy. I don't have firsthand experience with the Ritsee A7 specifically, so I wouldn't want to give you the wrong info and cause you to waste money. I'd suggest contacting Capella directly or popping by a baby fair or authorised retailer like Mothercare or Baby Kingdom where the staff can check on the spot for you lah. Hopefully someone else in the community has tried this combo and can share more.