lineone email address hacked

Hi all

my 17 year old lineone email account has been hacked

all of my contacts are receiving multiple spam emails

I can log into webmail but cannot log in to my account to change the password on my email account

I have used this account for 17 years with no issues and am 99% certain I have not been compromised at my end

(avg,malwarebytes etc show no issues)

is there any way I can change this password

many thanks

tony