Timbl Broadband Internet Service Provider - Internet services are not provided even after fully charged

I got connection of Timbl broadband in August **** in a hope that at least I will have some good connection to ease my work from home. Since **th September night, there is no internet connection. Even after multiple follow ups, they are not fixing the connection. When asked for full refund as I am not getting services I paid for and it is impacting my work, they blatantly denied saying that they will just refund the security amount. Due to their carelessness in fixing the issue, I have had a loss of work and pay. I have called them daily and even raised complaints on their online portal but no response yet. No call backs arranged as promised on every call.