Groupon is in trouble with regulators again after a promotion for breast enhancement failed to deliver the boost promised, and a discount deal on an Ocado product that never existed.

These latest breaches of the advertising code – Groupon's 49th and 50th this year – come days after the Advertising Standards Authority referred the deal-of-the-day website to the Office of Fair Trading.

The ASA made the referral after 48 breaches in 11 months, asking the OFT to look at concerns including running unfair promotions and the exaggeration of savings that can be made.

The first of the latest two rulings involved a promise that women who took advantage of a Groupon deal to have breast enhancement sessions with "microbean energy technology" would see "typical growth between a quarter and two cup sizes within five to eight weeks".

The ASA received a complaint that when a woman attended the spa, she was told it would take "a greater number" of treatments to achieve the growth claim.

It turned out that the claim was made on the basis of only six patients, which "was not sufficient evidence to substantiate the claim that the treatment was capable of achieving breast growth". The promotion was deemed to be misleading.

The second promotion was a deal for Ocado, which mainly delivers Waitrose groceries. The promotion made a claim of offering a one-year mid-week delivery pass "usually priced at £69.99". The ASA received complaints that the price was misleading because on 28 July – when the offer was launched – a six-month delivery deal was just £14.99.

There was also an annual delivery deal priced £69.99, however this was for deliveries on any day of the week the customer desired.

It transpired that at the time of the offer, there was no annual mid-week pass that was "usually priced at £69.99".

"In the absence of any evidence that compared the value of the promoted pass at £69.99 with an equivalent product, or that demonstrated how this price was calculated, we considered the 'value' of the promotional item had not been substantiated and therefore concluded that it was misleading," said the ASA.

"We take any claims by the ASA very seriously," said a spokeswoman for Groupon. "Providing clear and trustworthy information to our customers is of utmost importance to us."

In the case of the ruling against the beauty treatment, Groupon said that "we regret that we relied on our partner's data for results and didn't conduct our own investigation".

"We have made and continue to make enhancements to our quality assurance process to verify claims made by partners," said the spokeswoman.

Groupon said that in the case of the Ocado deal it does advise partners not to run multiple deals at the same time that might cause for confusion.

"We regret any confusion this may have caused," the spokeswoman added. "Going forward, we will also clearly mark new products or products where the value is not immediately obvious on the partner's website or in the marketing information."

• This article was amended on 15 December 2011 to clarify a description of Ocado.

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