New liner installation- problems- advice needed

[Flamingo]

Hi everyone. We've just had a new vinyl liner installed on our inground pool. We have had a few issues. They said they were finished, but when I went to go out and check it out, I noticed one of the jets wasn't there. So, they forgot to cut that out for one of the jets. At this point the pool is fully filled. I know they did the cut outs for the other jets while the water wasn't fully filled. So, the owner of the company came back out and cut out the hole for the jet (with pool fully filled) and turned the filter on and said its all fixed. I appreciated this and all was good for a few hours. After a about 2 hours, I noticed the liner bubbling up in several places and the pool lost a considerable amount of water. What could the cause of this be? I called them back, and they are coming out to inspect, but he told me on the phone I must have a broken plumbing pipe because that is the only way this could happen. The filter and plumbing were working fine all summer prior to the new liner installation. Anyone have any insight to the cause of this?