10000mh powerbank which I bought 2 years ago keeps disconnecting

Generally power bank will have two sockets in it. One is for charging it from the charger from the mains supply and other is for taking power from it to our device.
You have to now observe at which side (which socket) you are having this problem. If problem is coming when you are charging the power bank from the mains then you can check or replace those connectors and if it is happening at the time of taking power from the power bank then you can change that connector which is coming to your device (mobile). Sometimes due to the loose connection in the end of the connectors this type of thing can happen.
Another possibility is that if there is a hide and seek type of problem inside the power bank then even by changing the connectors you will not get relief and then the only remedy will be to get the power bank repaired.
I am not very sure whether power banks are so easily repaired in the market or not. Anyway you can try with some local technician for the solution in this matter.

Power bank is equipped with two sockets where in the first socket would draw from the main for its recharging and the other one would relay power to the device with which it is connected. Since you have observed that it becomes nonfunctional many a time, you need to check the wires whether they are connected with the terminals tightly or not. Chances are there that the wires are not properly secured in some terminal points causing dislocation of a full circuit. This can be checked from your end and with your homework, this can be resolved.
If the problem is not rectified from your end, it needs to be repaired by an experienced technician with the opening of the entire assembly to detect the internal flaw.
You will have to look out for such a technician and if you don't find one, you will have to replace with a new purchase of the power - bank.

Generally, power banks will work for 2 to 3 years only. It will work for about 500 to 1000 charges only. As per your statement, it is 2 years old. Probably the life might have been over. Anyhow try to do the following.
If the problem is in charging the power bank you can check for the following,
1. Cross check the charger you are using with any other device and confirm that it is working properly. If it is not working, you may have to change that.
2. See the charging port condition. If any dust or similar materials accumulated means, you have to clean the same once.
3. Try to use the original charger. In the market, we are getting many duplicate and cheap chargers. They will spoil the device also.
If the problem is while the power bank is charging the other device, you check for the following
1. Check the charging cable and port and ensure that they are working properly. Otherwise, change the charger and clean the port.
2. Before using the same try to see that the charger is having a minimum charge. If the charge is very less. it may not work properly.
3. Some power banks may not work if the device that is getting charged is fully charged. In such a case, the power bank may get switched off.
4. If there is any loose contact, the power bank will get heated up and get disconnected.
After checking all the points also if the power bank is not working properly show it to a technician who knows the mechanism completely. Never try to open the power bank on your own unless otherwise, you know the complete mechanism of the system. The mechanic will see that same and suggest you accordingly.