Airtel — no. postpaid to prepaid and bill complaint

I currently live in noida and i use two postpaid numbers of airtel. One of lucknow and one of noida. I wanted to get my lucknow number converted to prepaid and so i called customer care and they asked me to visit nearest airtel store for the same. When i visited there they told me that my lucknow number could be converted to prepaid only from lucknow. So, again on my next visit to lucknow i went to airtel store and due to server issues they asked me to visit an airtel store in noida to get my number converted to prepaid. When i had a talk on customer care they clearly refused to get my number converted to prepaid from noida. Now unnecessarily i will be paying extra amount as my bill even though i don't use that number coz roaming charges are applicable on that number.
Lucknow number is+91-[protected].

Also, on my noida number the application is showing the payable amount to be 649 while the e-bill shows payable amount to be 200-250 l. On customer care they told me that it music be some technical issue and i have to pay 649 only.
Noida number is -+91-[protected]