I’d say “У нас есть одно [о чём речь шла ранее] с помощью которого вы/мы можете/можем...”

If "one" is something that was mentioned before, not the quantity?

Right, it’s probably a solution, plan, etc.

Perhaps Katherina will give us more context.

If, for example, someone's advertising their advanced accounting course, is it possible they're addressing their target audience¿ saying something along the lines of "If you're looking to take an advanced course, we have one to support blabla..."?
If my suggestion's correct, I'd go with Uly's version - у нас есть то, что поможет вам непрерывно развиваться в профессиональном плане.

That exactly how it sounded to me.

👍🙏