As I see it you have two choices.
The first is if you really want to outsource your printing, you will need to find someone local to you - within easy transport distance - because you will want to pick up your printing. You know your locality better than anybody else on BC.
The second is to upgrade your printers. Almost all printers come with guides about their maximum sustained throughputs, often as copies/month. If you are exceeding these guidelines on a routine basis you are asking for failures. Commercial grade printers will cost you quite a bit more per printer initially but, if they are rated for your workloads, they should last a lot longer.