I have been subbing for 6 months and its been great except for the receptionist putting me down. Help!?

I really love these kids and this school and am working on my degree soon. I dont know what to do when all is well and then she attempts to ruin my name with lies and slander. She has bragged about how she has hurt other subs and yet noone truly stands up to her. Its not that im not wanting to work anywhere but hear but i have invested alot in these kids and teachers like how i do so they call me back. I dont want to not be able to work normal because of one cold person. Any adive is welcome!!!