In the spring of 2012, I attempted to graft a Pear scion onto my apple tree using Winter Banana Apple as an inter stem. (All of he grafting i do is "Whip and Tongue" grafts wrapped in grafting tape. I then coat the wrapped union with grafting wax) The parent branch was a Winesap Apple branch with a grafted Winter Banana Apple scion from a few years before. (I actually have two of these paired branches.) I then attempted to graft two "Kieffer" Pear scions onto my two Winter Banana Apple inter stems. The "Kieffer" Pear scions started to grow, but died a few weeks later. This spring (2014) I attempted to graft this Apple / Pear union again using the same Winter Banana Apple inter stems. I had just enough branch on my Winter Banana branches to try this experiment one more time. This time around, I used "Sunrise Pear" scionwood. The grafting was a screaming success! (I had enough "Sunrise Pear" scionwood to graft two branches onto my apple tree, and two more onto an ornamental pear. All four pear grafts were a success!) I have no idea why this experiment failed in 2012 and was a success in 2014. I do not know if it had to do with the pear variety used, or if it had to do with environmental circumstances. I will re-post in 2015 with an update. There are a few different treads on this subject so I will be re-posting on those threats also. Below are pictures taken on 07/27/2014.

Removing the plastic should be done carefully, which is probably what you have done. The plastic can cause issues if left on too long, so getting it off after 3 weeks is good. If you have high humidity outside, this would just exemplify issues inside the bag of plastic. They should not be in full sun. Should be kept in filtered sunlight to shade w the heat still until you have new growth coming from the scion. Sometimes the scion just do not take for what ever reasons and I will not go into that. Redo if you have more scion material available. Rick

I am not sure where you are located Vrinda, but there are two facebook scion exchanges going. You might get help there. One specifically for Canadians called the Canadian Scion and Edible Plant Exchange https://www.facebook.com/groups/506465963387694/ and one for North America named North American Scion Exchange https://www.facebook.com/groups/scionexchange/

What are you using to wrap the scion/graft area? I have more luck with veneer grafts rather than cleft grafts for the more difficult plants. I use perforated Buddy Tape, and then wrap the grafted area with a rubber band to assure good contact. Make sure cambium layers line up as best you can. Depending on where you are, you may need to shade the scion from full sun so it doesn't overheat.