PG Glass Service

six months ago ( October 2017) I took my car to PG Glass to fix my windscreen and it was recomended by my Insuarance Momentum, my windscreen was replace but after i noticed a leak when it rains but small plus my car never slept in the rain to see how big is the leak. Recently we experienced a rain the whole night were my car slept outside and when I woke up in the morning the car was wet on the roof where the windscreen join the body and some water in the tray, then first thing when i got to work i had to take it to PG Glass and showed them. one of their technicians checked it and after he ask me for an invoice which i didnt have. we went inside and they tried to check on the system using my details, I gave them myID number, my claim number and the name of my insuarance and my policy number but they told me they can't find anything on their system. I even called Momentum because I have changed insurance now but Momentum verified my details and gave me the claim number and i told them it didn't work but the lady from momentum told me she will take it further so that PG Glass can be contacted to resolve this so since wednsday 11th April 2018 I still waiting for a call. How possible it is for a company to fix a car and withing 6 months they dont have details of it. the leak almost damaged the car if it reached sensetive part I was lucky it went only in the tray. I really dont know what to do now because I even I asked the lady at PG Glass what should I do and She told me there is nothing she can do, so my question is a client come and say you offered a service to them and forward you informations (emails with claim number as proof) from the insurance with regard to to service, its the resposibility of PG Glass to find out what happened they should have called insurance and verified the informations I provided because now I am still waiting, they didnt even give me an invoice, only a piece of paper saying the replace the windscreen and I should keep that and file it.