Dont deliver what has been promised

Called coverage as I have been complaining about a network signal in my house, I was then promised a network booster device to be installed at my house, the promise happened in january. Last week i have decided to call and find out when are they installing the device, I was told that they sent me a disclaimer form on the 8feb and I should sign and resend to them, I never got the email, I called everyday and its the same this, they have escalated the matter to the superviser of that department. MTN you dont value your customers at all.