Paid in full, still waiting??

Still waiting for parts which have already been paid for. Sent my bike in to sort out an oil leak and recieved it back with the same oil leak. Paid for parts as an additional request to be fitted prior to collecting my bike. Upon collection the additional parts I paid for had not been fitted or ordered yet I paid for this in full. Promises were made to supply and install the parts once they recieved them. Ignoring my calls and messages for 6 months now after I have already paid in full for parts due to me.