Hi, welcome to GoY, you have probably done nothing wrong, these are epiphitic plants from rain forest's in southern Mexico, central America, south America and the west Indies, ideally they should be grown in a warm greenhouse, either epiphitically or in epiphitic bromeliad compost, in bright filtered light, and low humidity, but you usually find that when you buy them, they're in ordinary compost, which doesn't drain well enough, plus by keeping the "cup" full of water, you will probably find that the roots have rotted, or the bottom of the plant has become detatched from the roots, unless you can give them ideal conditions, you can only realistically only expect to keep them until the flower fades, so not your fault, Derek.