Worst Customer service experience!

Worst customer experience I have ever experienced. I have now tried to sort an issue I have with them for 2 weeks. Notes were made on system that query was escalated to management and I even spoke to a manager who always confirmed that the services I received is unacceptable, then promised me to get back to me by latest 15:00 the following day....but yet again no feedback. Every time I had to follow up, explain my situation again and again and again and my issue is still not sorted.