I have a problem  

RE: I have a problem

Good Morning, 

there is Hope for your printer...  

the Heater wire has broken on your extruder. 

currently Prusa don't list available spare parts for the heater, however 'e3D online' do list spares

https://e3d-online.com/prusa-mk3-hotend-spares

If England is not a good location for you, there are resellers in other locations

https://e3d-online.com/resellers

for the Mk3 and Mk3S Printer, you are looking for a 40watt 24volt heater. 

If I was ordering spar parts at this time, I would order two heaters and a Hot end thermistor. 
the thermistor wires are very delicate, and may get damaged while making the repairs to the heater...  
If you don't need the thermistor this time, you should end up with a spare heater and thermistor, for the future, and if you do damage the thermistor, you have one to hand, to save further delay.  

If all  goes well, you will have a spare heater and thermistor, on hand in case you get a Blob of Doom, and damage them trying to remove the blob... 

regards Joan

RE: I have a problem

Looking at the pictures there is a little bit of fraying on the sleeve. That suggests that it has been rubbing on the heated bed connector. Not enough to wear through but enough to cause the wire inside to move up and down. Done often enough it will snap the wire. I saw this when calibrating and have tried several times to move the sleeves up and away from the printed strain relief block. You could try rotating the heater in the heatblock slightly to make the cable behave better.

Andrew

RE: I have a problem

Knowlegdebase articles

https://help.prusa3d.com/en/guide/how-to-change-a-heatbreak-heatsink-heaterblock-mk3s-mk2-5s-mmu2s_16104

https://help.prusa3d.com/en/article/hotend-disassembly-heatbreak-stuck-in-the-heatsink_112677

https://help.prusa3d.com/en/guide/how-to-trim-ptfe-tube-original-prusa-printers_22424

regards Joan

RE: I have a problem

Thank you very much! 🙂