arguments

I recently bought a house on a buy to let basis,but the stress i am going through is incredible,i had someone to fit the new boiler,fire and bathroom,but my friend (who has terminal cancer) told me to get his other mates to do it and said they would be cheaper,i got a great quote from them and they have almost finished the work,they told me yesterday that the money they want is now over double the quote they gave me,and i told them i could have got it done alot cheaper from another guy i know,then he got quite upset and i did aswell and we argued(i rarely argue with anyone but i had to say something),i rang my friend and told him  but he took the builders side ,i ended up arguing with my friend yesterday and again today as the workmen took the  old copper boilers which i was going to keep as there worth about £70 for scrap,i am really skint at the moment and have had to borrow £4,000 off my dad to cover the costs.The builders never askeed me for the old boilers or told me they took them ,i feel like there taking the piss and im really upset about the whole thing,my friend has only months to live and i regret arguing with him,but he takes no responsibility ,i am so f**king sick.