Tenant not responding

Rent Arrears

Hi, one of our tenants is constantly in arrears each month, her guarantor (her mother) pays in dribs and up until this month has alwys managed to pay her daughters rent. this month she is still owing half of the rent, I have tried contact her but with no response. The tenant is on housing bennefit and they have agreed to pay me direct which will be 4 weeks in arrears. there is a shortfall in the rent which the tenant will have to pay.Her 6 month short hold tenancy ends the end of July. I will not be re newing the tenancy, what's the procedure to evict her . Many thanks.