Worst sun protection ever experienced

I bought the family pack of soltan creams (factor 15, 30 and kids 50) to take on our honeymoon, along with a bottle of P20 and a bottle of piz buin.. I've tried all different sunscreens over the years and always found them effective enough to ensure I never actually burn, until now! My husband started off using the Piz Buin and I used the Soltan. Our first day at te beach I followed the directions on the bottle and applied the cream generously, reapplied regularly, went for a swim in the sea and then reapplied shortly afterwards. Not long after I started noticing a pink area which I spotted because I'd applied a separate sunblock stick to a recent scar which was still white. I went and sat in the shade straight away for another 20 minutes or so and then as things were getting redder said to my husband I was heading back to the hotel. That evening I was bright red everywhere where my swimming costume had been and on my back and front where I'd been lying
on my towel despite me being very careful to apply the cream under the straps and costume had been. Ultimately, the soltan had been rubbed off very easily and had offered me no protection whatsoever and I had white patches everywhere I'd used the Uvistat sunblock. I ended up spending the next day in the room while my husband went to the pool wearing his Piz Buin and the following few days wearing the p20, sunblock and dodging the sun as much as possible. Nightmare for our sunny honeymoon. I'd almost decided not to write this review except for what happened today. We ran out of Piz Buin and had nearly finished the P20 and as we're on an island in a country where you hear horror stories of people manufacturing fake suncream my husband said he would use the Soltan and I used up the last of the P20. We didn't go swimming at all, lay in the sun for about 40 minutes as then moved into the shade. I was fine, no signs of any tan at all with the p20, but my husband has ended up with a burnt back thanks to Boots Soltan factor 30 and 50 for kids (bought in the UK), which again appears to have just rubbed off with a bit of sweat and lying on a towel. I honestly don't know how they can market this as a water resistant sunscreen as any sweat or dampness from a drying costume WILL remove it and you might burn. We will never buy Soltan ever again and urge anyone reading this to rethink. If you have children please don't risk it, I've never ever been so shocked by a sunscreen before. We've said from now on we'll only use p20 or now I think they do a p50 which we'll also try. One application in the morning, lasts all day including swimming and sweating and so much more effective than soltan 30 or 50forkids. Agree with other reviews that it stained clothes yellow, so did p20 but we don't care about that, just that we won't get burnt again in future.