Sorry Rewy, if it's never shown any signs of life in two years, it's dead. And dead is dead - no amount of watering or care now will change that.

If you're now in a position to take an interest in your garden and want to plant a tree to replace it, you'll need to get the old one out, dig a hole quite a bit bigger than the pot containing the prospective new tree and remove any old rubble and building debris you come across. Add compost to the hole and mix it with the surrounding soil, breaking up the compacted soil on the bottom so that the tree's roots meet a mixture of soil and compost and can get down to where the water and nutrients are. Add some slow release fertilizer (granules or blood, fish & bone) if you like to the broken up soil / compost mixture. Water your new tree well, open out its roots gently if it's pot bound and plant in the hole, backfilling with a soil / compost mixture and making sure that the soil level ends up where it was when the tree was in the pot. Don't have it higher up the trunk. Heel it in gently and arrange a little dam of soil in a ring around the trunk, about 2 feet in diameter, so that when you water it, the water stays by the tree and doesn't run off elsewhere. You'll need to make sure it gets watered thoroughly, by you or by rain, every week for at least a year.

If it's all just too much, go for something else. A small shrub surrounded by tough perennials like euphorbia, epimedium and hardy geraniums would take a lot less digging and aftercare, and be a lot cheaper.

It is possible that it never survived being transplanted in the first place. If the soil or light is not right for the tree then the tree will not survive (developers only need to plant a tree or plant if it is in the plans regardless if it is suitable - I have seen wrong tree types planted in clay and shade loving plants in full sun). If it has never produced leaves then that is not good. Is the bark coming away from the trunk and does the branches snap when bent?