Cancellation issue

I logged a cancellation request in February. no update and no feedback since. when i log into the self service portal. my query still shows as being investigated. February 2021, last update was at 12:16 18th May 2021. Still no resolution. Now they have suspended my number because they were billing me during this period. Now i can't use the number anymore and i have critical services tied to that number! Please can this be resolved ASAP! Now they are saying I owe them, and threatening me using debt collectors from P&P but my cancellation request from 2021 is still not resolved.