Credit limit increase

I requested to increase my credit limit on 04/11/2015. I completed the form and no one came back to me with feedback. I phoned customer care and I was told I have to provide them with proof of income. I provided that on the 01/12/2015 and I was told I have to wait for 3 days. I went to Bushbuckridge on the 08/12/2015 and the lady on the till told me it takes long and she can't do any thing about that as I might not afford. My question is how can someone tells me that I can't afford without checking. How long exactly do I have to wait for feeback?