Renault review: Not received service I paid for and items ticked on service sheet had not been done.

On 4th February I took my car for an essential service to Renault Sefton Street Liverpool. I had also asked for a car health check as car was creaking at the front.
Picked up my car later that afternoon, and was informed of work that needed to be done and given the service sheet with all checks ticked that should have been done.
I had decided to take my car to another garage to get work done that was highlighted through the health check. When my car was checked, with myself & husband present, it was found that the coolant container was bone dry and my engine oil was low and very thick and sludgy. I would not have known about this unless I had taken it to another garage and the lack of coolant and low oil, could have damaged my engine.
Both of these things had been ticked off as done on the service sheet so we rang Renault to complain and spoke to the manager who asked us to bring car back on Saturday 6th to be checked again and they would talk to the engineer who serviced my car.
Due to Covid restrictions we could not wait in the showroom while they looked at my car and was left to wait outside in sub-zero temperatures for 90 minutes and we were both feeling quite close to hypothermia which took us a full day to finally get our body temperatures back to near normal.
When they finally gave car back, we were informed that the service manager would be ringing us the following Monday to speak to us about it and that the engineer who did the service on 4th had not done his job and ticked boxes he shouldn't have.
Since then, the service manager has contacted us and when we ring Renault to ask to speak to him, we are just told he will get back to us as he is working from home. Very frustrating and abysmal customer service!
Firstly, I have not received the service I paid for and secondly, the service engineer blatantly lied on the service sheet by ticking jobs that clearly were not completed and could have damaged my car if they had not been discovered.