Boiler coming up but heating and hot water not working?

Hi, I have a myson orion boiler in my flat. Someone came around this morning to service the boiler but I found out in the end (after he claimed to have serviced it and everything was working fine) that he was at the wrong address. Tonight I turned the boiler on only to find out that my heating is no longer working and I have ran out of hot water. Please can you help with this? Thanks in advance