Non existent Upgrade

I have been trying to upgrade my contract since the 3 February without success. First i went to the store and was told I`m not due for an upgrade on the system, but i received an email informing me that I can. I that contacted the retentions department and was told my account is suspended but the payment was made on time via debit order. The agent said they in contact with the accounts department to sought out the issue and once thats done he will assist with my updgrade. The last correspondence from the agent was on the 7th, no response after numerous attempts to get a hold him. I called and spoke to his second in charge on the 11th she advised me that I can do the updgrade in store, went to the store the same day they still couldn`t proceed. I tried to lodge a complaint today but it doesn't seem like anyone knows where the complaints department is.