What should i do about it?

i have a friend shes like my bestest friend i been friends for 6 years but she has a hard life cause of her dad and some other issues but she really likes me as her bestest friend but theres things about her the way she is with a tesco i live next to backchatting the secuirty guard and getting barred from there and i hate how she likes hanging out there and i dont like it and i tell her but she begs until she gets her own way shes just being stubborn and we never really do what i want to do she rings me like everyday and begs me when i say no im busy i tell her but she acts like shes stopping me and she seems like a total chav wearing a hoody and hanging round with scratty 13 yr olds she truely is a nice person but when she backchats, wants her own way and behaves selfish its not ok i dont know what to do about her