Is there a guarantee on the fix?

Yes. A Quick Fix carries a 7-day warranty on that specific bug, if it recurs, we fix it again at no charge. A Bug-Fix Sprint includes 14 days of post-fix coverage. Because every fix is reproduced on staging and regression-tested before deploy, recurrences are rare. For ongoing peace of mind on a live OpenCart store, an Emergency / Retainer keeps you in a priority queue.