Lack of service

After phoning customer care line on the 24th of Apr to apply for an increase on my overdraft, I was told that the application was provisionally approved. I just needed to submit 2 documents, proof of address, and latest payslip. This was done later that evening and quoted the reference number that was given to me. I was told the process would take 2-3 days. I submitted the documents on the morning of the 25th of April. It is now 5 May, and I have not had any feedback yet. Why is it that we always have to complain first before getting any service from service providers these days...