The SNP minister’s was responding to claims from the Scottish Tories that he still had “something to hide” and was “covering up the truth from taxpayers.”
They said Holyrood’s IT department should fully examine the tablet to ensure that the eye-watering bill related “solely to parliamentary and constituency-related work”.
Last week, following days of controversy over the invoice, Mr Matheson agreed to pay back the £10,935.74 incurred in roaming charges during a family holiday in Morocco.
Initially, the SNP minister was only going to pay £3,000 towards the cost from his expenses budget, with the Scottish Parliament agreeing to pay the rest.
However, Mr Matheson, who has an annual salary of £118,511, said on Friday afternoon that he would reimburse the full cost.
But Scottish Conservative chairman Craig Hoy has called for a statement on the matter, and said the public deserved “full transparency on the matter”.
In a letter to the Health Secretary, he urged Mr Matheson to set out what steps he had taken to “protect public money and keep costs low, in line with the value for money requirements set out in the official expenses policy”.
Mr Hoy added that the minister’s “belated commitment to pay for these roaming charges in full should not distract from the fact that such a large bill does not represent value for money for the taxpayer”.
The Tory said: “Mr Matheson has many serious unanswered questions to address, which is why I have written to him requesting that he make a statement at Holyrood this week so that we can get to the bottom of this scandal.
“A failure to answer these questions will further add to the public’s suspicion that Michael Matheson has something to hide over this scandal.”
Last week, Mr Matheson said the bill was brought about by using “an outdated SIM card in an iPad that I had for constituency purposes.”
He insisted that he was not aware that this had to be replaced, and that “the cost built up as a result of that.”
The Scottish Parliament said their records show Mr Matheson was informed by email in February 2021 of the need to change SIM cards from EE to Vodafone.
Speaking to reporters at Queen Elizabeth University Hospital, Michael Matheson told the media: “Parliament investigated this issue, keep in mind, back in January, where one of our senior IT officials looked into it and came to a view on this matter.
“That’s why I took the personal decision, as I said in my statement on Friday, that I will reimburse the Parliament for the full costs of that.”