The most likely reason is that the hot water valve is turned off in the bathrooms. Look under the bathroom sink. There should be two valves - the one on the right controls the flow of cold water and the one on the left controls the flow of hot water. Turn the hot water valve counter-clockwise to open.
Have you checked to make sure the hot water hasn't been turned off? Look under the sink and turn the wheel that's below the hot water faucet. Turn it to the left to open the hot water.
That water is used in the cold taps in your bathroom and for the heated water you use. Don't drink from these taps.
There are many places where one could purchase bathroom sink taps. One could check online shopping websites such as Amazon or eBay for purchasing bathroom sink taps.
It means hot water while the blue side means cold
Microwave. Digital scales, Instant boiling water taps.
Home Depot sells a wide variety of Kitchen Taps ranging in price from about $15 to upwards of $500. They have taps with built in soap dispensers and nozzles that can spray.
There seems to be no company with the name Kitchen Sinks & Taps. There are several home improvement online stores and brick and mortar stores that sell kitchen sinks and taps. Each one having a website from different years.
You can call a handyman or a plummer in your area to help install your kitchen taps. It should not cost more than $50.00 to do this.
The cutoff valve from the hot water heater may have been closed.
aluminium
it is made of some sort of metal
If the taps and the spout are not connected in one unit, the spacing on your sink is probably 8 inches center to center. The only faucet I have seen for a bathroom sink with that spacing is the two handle type. There may be a single handle available. A kitchen faucet may work if the holes in the sink are large enough. Kitchen faucets are 8 inch also. If yours is 4 inch, then it is no problem, they are common.
Kitchen mixer taps are available in a wide range of outlets both in the high street and online. These range from basic DIY shops such as B & Q to more specialist plumbers merchants and kitchen shops.