It sounds like the base station has failed or the phone has lost its pairing with the base station.
The base station is the device which plugs into your phone line, what lights are showing on it?
That sounds like our problem, can check the mains cable is switched on at the wall, and the plug is firmly in place on the base station.
In that case the most likely cause is a faulty power supply, this can be ordered directly from Gigagset here, they cost about £19 including VAT and delivery.
Please let me know if you need any further assistance.
The power supply which is the plug which goes from the mains socket to base station has failed, its not providing power to the base station. As such this part needs to be replaced, it can be ordered from Gigaset via there website, if you click here, you will be taken to their website where you can order a replacement.
Please let me know if you need further clarification.
You can also order the part from amazon at the link below for £12 including delivery.