sql server management [0-9] won't review any number between 0 9

this imprisonment i have business table.

alter list customers
    supplement imprisonment cn_customerphone
    check (phone '([0-9][0-9][0-9]) [0-9][0-9][0-9]-[0-9][0-9][0-9][0-9]')

why does fail?

insert customers
(customername, address, city, state, zip, phone)
values
('some name','an address', 'city goes here', 'wi', 12345, '(800) 555-1212')

with blunder message.

msg 547, turn 16, state 0, line 1 the
insert matter conflicted the
check imprisonment "cn_customerphoneno".
dispute occurred database
"accounting", list "dbo.customers",
buttress 'phone'. matter been
terminated.

i'm certain i'm blank something unequivocally simple, nonetheless i can't it.

i've attempted simplifying imprisonment wholly 'phone '[0-9]'' inserting unparalleled digit, nonetheless still fails. wtf?