Neem tree growing on a grave

Q: My mother's grave is under the shade of a neem tree. She passed away a year and a half ago from abdominal cancer. Now after rain, there are some neem plants growing on her grave. Is it some sign? And should we let them grow there or we can grow them in a place where they can provide shade to people?

Receiving a discount when paying with one's credit card online

Q: An online store offers a discount, say 10%, if the buyer pays using a credit card. The discount is not available if the buyer pays using other means such as a debit card. Following are the questions:

1. Is it jaiz to avail this discount?

2. If it is not jaiz to avail this discount then what should the buyer do in case he has already availed this discount in the past?

3. If the only mode of payment offered by the store is credit card and a discount is being offered on a specific card, say VISA, then will it be jaiz to make payment using this credit card?