Disappointed customer service

I was approved on the 30th of August for a new contract It’s now almost a month later and I’ve been pushed around from pillar to post by there team just to get a sales agent to call me and finalise my deal I’ve called every other day and it’s been you will receive a call in 24 hours It’s been almost a month and still nothing I have asked to speak to a manager but nobody wants to put me through to one. I am disappointed as I’ve had a contract that took 1 day with them but now it’s unacceptable and frustrating that this is the level of customer service I’ve been apparently made a priority about 3 weeks ago and still nothing