My shark vacuum cleaner on they did not get the number

I purchase my short vacuum cleaner March 17th 2020 I got to tell you I have been trying to get them to take this one back that has glitches and replace it with one that's functioning 100%, now they told me I would not take it back but they would give me another one with 70% off really how is that within the warranty and I'm well within the warranty since I've only had it since March and if they're going to have people buying their vacuum cleaners too sell to people why would they make it so difficult to correct a problem caution in buying the shark vacuum cleaners or any robot vacuum cleaner