There's a big difference between 1 chargeback out of 3 sales and 1 chargeback out of 200 sales so it would be good if you'd let us know your expected chargeback _percentage_.
In general though, almost every reliable merchant account provider gets suspicious whenever your CB rate exceeds 1%. This, for you, means either an increase in reserve or in worst case the termination of your contract.
If that's the case then what you're looking for is a "high risk merchant account". Google for it. But be careful and look for reviews as many high risk merchant account providers aren't very big on .. umm .. business ethics, so to say.