I see at least three different aspects of your problem.
Ho is your product owner? Or who is deciding on priorities for your product? You are saying that fixing those bugs is not so good for improvement of the product, but maybe it is. If you clients rise them as critical then maybe this is where they find the most value for them. After all we want to deliver the most possible value.
Ar they really bugs or some small ad-hoc change requests? Again they might be more valuable to the clients.
I assume that if you are posting this problem here then your clients are flooding you team with those requests but in the other hand they are not satisfied with the number of let's call them "real new features" you deliver at the end of your monthly iteration?
To handle no. 3 you may try to convince the clients and the product owner that you will for the next few iterations accept only some amount of those patches and leave space for 2-3 features. However this is risky for me, as you need to answer one more question:
Why are we flooded by those bugs? Why there are so many of them. Maybe there is some quality problem within the team/process and we should first find a way to stop those bugs from going out to production?
So to sum it up:
- Find the root cause of the so high number of bugs because it's paralyzing your team's velocity.
- Prioritize those requests withing your product backlog as you do with the features - you need to be sure that you clients really see them more valuable than the other items.
I know to little about the full context of your project to give some more detailed advice.