Vacuum storage bags

Ah, sorry - I see that you've tried doing it by hand with no success. How about using a freezer clip along the seal, pressing it together firmly?

I have no clue where they were bought but thanks anyway.

Do the bags have a channel along the top on one side with a corresponding plastic lip on the other side that fits into it? If so, I've found that starting at one end engaging the lip in the channel and running my finger along seals it up. A bit like those freezer bags that you can buy with a similar sealing system.

You only need one clip, which you can add or lift off as needed. I have a few bags without clips and that is how I re-use them

I'm presuming that you've contacted the Manufacturer , obviously- no offence!
Other than that I've no suggestions.

I understand what you mean. But I dont know the answer, so am bumping for you.