I'm not entirely clear about problem. Firstly does it give both horizontal and vertical beams, eg cross wires, or does it have a single beam, or selectable beam types?
Is just one of the beams 'duel', or are they both/all the same?
Do you mean two beams side by side, or a fuzzy wider beam than you expected?
Sorry about all the questions, just trying to visualise the problem. As usual a photo would help if you can do that.
It sounds to me like an optical issue, and a good reason to return it! Not normally the sort of thing you can fix if its got a faulty lens or damaged component In the optical path.