Blacklisting/No answer at call centre for days

I have been trying to blacklist my phone since last Tuesday. Comfort in the risk department apparently still hasn't done it. Over the last week every time i call your customer service number i go through all the prompts and the line just hangs. When it does ring you get put down or told \its high call volumes sorry"and then the line goes dead. I have been trying all morning and cannot even get through to somebody to help me. This service is appalling. Everything you have touched since my contract was transferred from Nashua Mobile to you has been a stuff up. Whether it be reconnecting the line which i lost for 2 days or debit orders you forgot to collect for 4 mths and then wanted to suspend my account. I try completing your online query form and it says someone will help in 7 days???? I need to process my insurance claim and cannot for a week because of you. I will be cancelling my contract today. """