Lenskart — Bad after Sales Sevice at Store and by Regional Manager Mr Naresh

I had orrderred a Sunglass Frame on Lesnkart App and the same was delivered as per expectation. After receiving the frame, I wanted to use the same as my power glass and hence I went to their Store at Subedari, Warangal.
At first, they refused to provide the services. After a long discussion, they agreed to get the work done and informed me that it would take 6-7 days. I was ready to make the payment through a Credit card, but they refused to accept payment through a Credit card and insisted on payment through Paytm. Again after a long discussion, they agreed to get the work done and then I would be asked to pay.
However after 6 days, today I got a call to make the payment to start the work at their end.

My two questions to Lenskart are:
1. Why you wasted 6 days and then again insisting the payment before starting the work?
2. Why you refused to take payment through a credit card.