Yes, 4 cancellations affect quite a lot. If I (small profile) got them, I probably wouldn’t get orders for a month. Not to mention the completion percentage also works in a dumb artificial way which is super awkward and hurts everybody but bigger accounts, regardless of quality and other parameters.
Cancellations are better than bad reviews for your run anyways and levels/stats can return in full force after 60 days, unlike with the latter which can damn you if you’re just starting out or hamper you for life.
BTW, 4 cancellations in a week is too much of even for top sellers/graphic studios operating with multiple people, what was the cause? It might be time for some reporting or light editing on your gig(s) if there are too many misunderstandings. Also do as @imagination7413 says, IF you can do it through CS, (you’ll understand when you can by yourself), don’t even flinch or worry about bothering them and do it there, it might not hurt your stats.