How long before I should receive a decision?

My sons father best me up when he was just 5 weeks old (I left and never went back) he asked to see him after 6 months - I didnt refuse contact I just suggested he had supervised access in a contact centre only until I was satisfied my son wasnt in harm's way. Anyways ff to this year I went through the courts to gain permission for a passport for my son without his father's permission due to the fact I changed his name without his permission during the hearings, the father had spoken to the court and said he wanted nothing to do with my son and wanted his half of parental responsibility taking away from him. After 5 months and 3 hearings all is sorted and he bo longer has a say in my sons life and if he does decide in the future he wants access he has to apply to the court wich would be very difficult after he disowned him. Anyways I applied for child maintenance but I wanted to know how long it takes for me to actually get some correspondence of how much I should receive and when? It's been almost 4 weeks and I know it can take up to 6. I have phoned and asked but the lady on the phone wasn't useful and just told me she couldn't disclose anything over the phone and what ever I need to know I will get in the post she did mention that the father wanted something on the application changing but yet again wouldn't disclose this, thanks in advance for a reply :beer: