If you have just received your shears and they are bending the hair instead of a clean slice, it's likely they aren't tightened. Included in your box is a tightening key so you can tighten the shears so there is less space between the blades.
If you have had the shears for some time, you can have them sharpened so they are like new again. Only use sharpeners that specialize in hairdressing shears and understand concave sharpening techniques. Contact us for any questions before you send your shears off.