Some advice please on how best to proceed. (legal)

I had 3 x alloy wheels all with cracks.. I took them to a company .. gave them the wheels, they quoted £20 - £30 a rim... a few days later they rang me to collect and told me it was £150 as they were a pain. I fitted them.. drove down the motorway.. and 2 of the wheels have cracked straight back through everywhere thats been welded.
They confirmed they should not have cracked that easily.. but at the same time began talking about 'but theres no guarantee'. They have offered to reweld them to try again but have said they are unwilling to refund the £150.
Ive agreed to let them reweld them however have also said that as it was not made clear there was no guarantee to begin with should they fail so quickly again i will wanting my money back.
Today i left them a message to see if i can take them down to be rewelded .. they have read it.. but not replied. Thinking this may end up going to small claims, which is annoying on such a small sum of money.
I have some facebook convos stating.
'they will weld'
'They should not have cracked that easily' etc

What advice are you looking for DJ? Sounds like you're already taking this in the right direction :agree:

all sorted now, popped down and got my money.. anoying it took many weeks are arguements..

I messaged him and told him i was going to bring the wheels down whether hes there or not, i promptly got a response saying he will give me a full refund for the work.